Research Article
Research Article
A foundation monograph of Ipomoea (Convolvulaceae) in the New World
expand article infoJohn R. I. Wood§, Pablo Muñoz-Rodríguez, Bethany R. M. Williams, Robert W. Scotland
‡ University of Oxford, Oxford, United Kingdom
§ Royal Botanic Garden, Kew, United Kingdom
Open Access


A monograph of the 425 New World species of Ipomoea is presented. All 425 species are described and information is provided on their ecology and distribution, with citations from all countries from which they are reported. Notes are provided on salient characteristics and taxonomic issues related to individual species. A full synonymy is provided and 272 names are lectotypified. An extensive introduction discusses the delimitation and history of Ipomoea arguing that a broad generic concept is the only rational solution in the light of recent phylogenetic advances. Although no formal infrageneric classification is proposed, attention is drawn to the major clades of the genus and several morphologically well-defined clades are discussed including those traditionally treated under the names Arborescens, Batatas, Pharbitis, Calonyction and Quamoclit, sometimes as distinct genera, subgenera, sections or series. Identification keys are provided on a regional basis including multi-entry keys for the main continental blocks. Six species are described as new, Ipomoea nivea J.R.I. Wood & Scotland from Peru, I. apodiensis J.R.I. Wood & Scotland from Brazil, I. calcicola J.R.I. Wood & Scotland, I. pochutlensis J.R.I. Wood & Scotland, I. zacatecana J.R.I. Wood & Scotland and I. ramulosa J.R.I. Wood & Scotland from Mexico, while var. australis of I. cordatotriloba is raised to specific status as I. australis (O’Donell) J.R.I. Wood & P. Muñoz. New subspecies for I. nitida (subsp. krapovickasii J.R.I. Wood & Scotland) and for I. chenopodiifolia (subsp. bellator J.R.I. Wood & Scotland) are described. The status of previously recognized species and varieties is changed so the following new subspecies are recognized: I. amnicola subsp. chiliantha (Hallier f.) J.R.I. Wood & Scotland, I. chenopodiifolia subsp. signata (House) J.R.I. Wood & Scotland, I. orizabensis subsp. collina (House) J.R.I. Wood & Scotland, I. orizabensis subsp. austromexicana (J.A. McDonald) J.R.I. Wood & Scotland, I. orizabensis subsp. novogaliciana (J.A. McDonald) J.R.I. Wood & Scotland, I. setosa subsp. pavonii (Hallier f.) J.R.I. Wood & Scotland, I. setosa subsp. melanotricha (Brandegee) J.R.I. Wood & Scotland, I. setosa subsp. sepacuitensis (Donn. Sm.) J.R.I. Wood & Scotland, I. ternifolia subsp. leptotoma (Torr.) J.R.I. Wood & Scotland. Ipomoea angustata and I. subincana are treated as var. angustata (Brandegee) J.R.I. Wood & Scotland and var. subincana (Choisy) J.R.I. Wood & Scotland of I. barbatisepala and I. brasiliana respectively. Attention is drawn to a number of hitherto poorly recognized phenomena in the genus including a very large radiation centred on the Parana region of South America and another on the Caribbean Islands, a strong trend towards an amphitropical distribution in the New World, the existence of a relatively large number of species with a pantropical distribution and of many species in different clades with storage roots, most of which have never been evaluated for economic purposes. The treatment is illustrated with over 200 figures composed of line drawings and photographs.


America, Batatas, Convolvulaceae, distribution, illustrations, keys, lectotypification, monograph, morning glory, new taxa, Pharbitis, Quamoclit, revision, storage roots, sweet potato, synonymy


This monograph of Ipomoea L. in the New World follows on from our monograph of Convolvulus (Wood et al. 2015). Ipomoea, as here interpreted, is a large pantropical genus of about 800 species. We have studied the genus worldwide and supporting papers (Wood et al. 2015, 2016a, 2016b, 2017a, 2017b, 2017c, 2017d, 2018; Wood and Scotland 2017a, 2017b, 2017c; Muñoz-Rodríguez et al. 2018, 2019) reflect this comprehensive overview, but for pragmatic reasons this monograph treats in detail only those species recorded from the New World (i.e. the American continent and associated islands including Easter Island, the Galapagos Islands and Hawaii in the Pacific together with Bermuda, Bahamas and the Caribbean Islands on the Atlantic side).

We have developed the ‘foundation monograph’ concept at Oxford as an approach to overhauling the taxonomy of species-rich groups of tropical plants since many of these groups have never been studied across their entire geographical distribution as a consequence of the pragmatic and local nature of much taxonomy. Inevitably, these groups contain undiscovered species, high levels of undetected synonymy, and identification keys are absent or limited. A major challenge in monographing these groups is the size of the task given the number of species, their global distribution and extensive synonymy, the large and increasing number of specimens, the numerous and dispersed herbaria where specimens are housed and an extensive, scattered and often obscure literature. Our approach seeks to focus on those tasks that are tractable and can offer the maximum improvement in taxonomic knowledge in a given period of time. It is novel in the sense that we combine standard taxonomic techniques with the use of online digital images and molecular sequence data to focus on species level taxonomic problems across the entire distribution range of individual species. A detailed account of our approach is available in Muñoz-Rodríguez et al. (2019).

Although there are some problems of species delimitation in Ipomoea, particularly in Clade A (Figure 1; Muñoz-Rodríguez et al. 2019), we have been able to provide descriptions of all accepted species in New World Ipomoea, identify types and provide outline details of distribution and ecology for nearly all taxa. We have described six further new species and provided a complete synonymy, keys, illustrations and notes to facilitate identification as well as to highlight infraspecific variation and areas of taxonomic uncertainty. To avoid unnecessary redundancy authorities are not provided for taxa mentioned in the introductory section and notes, as these are all provided in the taxonomic account. Exceptions are made for first occurrence of taxa which do not feature in the taxonomic account or in situations where authorities are needed to distinguish between different applications of the same name.


Generic delimitation

Ipomoea as constituted by Linnaeus was based on Ipomoea pes-tigridis L. and contained various elements, including I. quamoclit and I. coccinea (Quamoclit Clade, page 556), I. triloba and I. lacunosa (Batatas Clade, page 387), I. violacea, I. alba and I. carolina as well as species of Merremia Dennst. ex Endl. and Jacquemontia Choisy and even a species of Hydrophyllaceae, I. nyctelea L. (=Ellisia nyctelea (L.) L.). It was not clearly defined and several species since treated as belonging to Ipomoea were placed in Convolvulus L. by Linnaeus including I. purpurea and I. pes-caprae.

Jacquin, Vahl, Willdenow and others of Linnaeus’ successors in the later part of the 18th century continued placing species of Convolvulaceae rather arbitrarily in either Convolvulus L. or Ipomoea. Only Cavanilles’ placements came close to coinciding with a modern concept of I.omoea. Some authors, like Desrousseaux (1792), maintained a wide concept of Convolvulus that included all species of Ipomoea and it was only in 1810 that a clear distinction between the two genera, based on stigma morphology, was established by Robert Brown (1810: 484). He contrasted the 2–3-lobed, capitate stigma of Ipomoea with the two filiform stigmas of Convolvulus. Brown recognized the ovary of Ipomoea as being 2–3 locular but made no attempt to subdivide the genus based on the number of ovary cells. Although Roemer and Schultes (1819) followed Brown’s classification, a wide circumscription of Convolvulus remained current for some time. Both Kunth (1819) and Sprengel (1824 1827) included Ipomoea within Convolvulus and it was not until the various publications of Choisy (1834, 1838, 1845) that Ipomoea was permanently separated from Convolvulus.

Choisy (1834, 1845) subdivided Ipomoea s.l. into several genera based on a series of ovary and fruit characters. He recognized a tribe Argyreieae Choisy comprising a heterogeneous group of genera including Argyreia, Rivea, Legendrea (=Turbina) and Marcellia on the basis of their having indehiscent fruits. The tribe Convolvuleae Choisy, in contrast, was characterized by having dehiscent fruiting capsules. In this second group, Choisy recognized Quamoclit, Mina, Batatas, Pharbitis, Calonyction, Exogonium and Lepistemon as distinct from but related to Ipomoea based on characters of the ovary and corolla. Quamoclit was recognized as distinct because of the 4-locular ovary, each cell with a single seed. Mina was separated from Quamoclit because of the suburceolate corolla shape. Together these two genera comprise what we recognize as the Quamoclit Clade (page 556). Pharbitis was separated on the basis of having a 3-lobed stigma and 3-locular ovary, each cell with two seeds, this genus constituting the Pharbitis Clade (page 430). Choisy’s Batatas was vaguely defined and is very heterogeneous comprising many extraneous elements besides I. batatas and I. triloba. Calonyction and Exogonium were separated from Ipomoea on the basis of their corolla, large, showy, white or pale lilac in the case of Calonyction but merely tubular in the case of Exogonium. A small clade of species of which I. alba is the best known more or less coincides with Choisy’s Calonyction, which was redefined and extended by Hallier (1897b). Exogonium was accepted by House (1908a) and other authors but is very heterogeneous and therefore polyphyletic, so bearing no clear relationship to the clades recognized in our molecular studies. Lepistemon was separated because of the large scales at the base of the stamens, a character that sometimes appears elsewhere in the genus, for example in some specimens of I. batatoides.

Choisy’s system continued in use until the 1890s when it was essentially reproduced in the account of Convolvulaceae in Die Natürlichen Pflanzenfamilien (Peter 1891). However, acceptance was never universal and Grisebach (1862b) reduced many of Choisy’s genera to sections of Ipomoea, a decision in which he was followed by Meisner (1869), Gray (1878, 1886) and others. Nevertheless, it was only in 1893 that a major generic reorganization was proposed by Hallier. The major innovation in Hallier’s (1893a, b) system was the use of pollen. He divided the Convolvulaceae into two pollen groups based on whether the pollen was smooth or spiny. The spiny pollen group, which included Ipomoea, was itself divided into two subgroups essentially on the basis of the fruit distinction proposed by Choisy for his tribes Argyreieae and Convolvuleae. The first subgroup (Echinoconieae subgroup Ipomoeeae) was composed of species with a dehiscent capsular fruit and comprised Lepistemon, Calonyction and Quamoclit as well as Ipomoea (in which Hallier included Exogonium, Pharbitis, Marcellia and Legendrea). The second subgroup (Echinoconieae subgroup Argyreieae) was characterized by its indehiscent fruit and comprised Argyreia, Rivea, Ipomoea tiliifolia and Blinkworthia. Two new genera in this second group were established: Stictocardia to accommodate I. tiliifolia and a few related species based on the prominent black leaf glands and strongly accrescent sepals and Astrochlaena (=Astripomoea Meeuse) to accommodate a group of mostly erect South African plants with stellate hairs and shortly oblong stigmas (Hallier 1893b: 159). For the first time Merremia Dennst. ex Endl. was clearly distinguished to accommodate species previously placed in Ipomoea but distinct because of their non-spiny pollen and generally white, cream or yellow flowers (Hallier 1893a). In fact, Merremia sensu Hallier represents a heterogeneous collection of species although dividing it up into natural genera is problematic (Simões et al. 2015, Simões and Staples 2017).

Hallier’s system has endured with only a few, relatively minor changes for about 125 years. A handful of new genera were established to include small, morphologically distinct splinter groups from the Ipomoeeae such as Lepistemonopsis with fleshy scales at the base of the filaments and Pentacrostigma with a 5-lobed stigma and 5-locular ovary. On the other hand the genera Calonyction, Mina and Quamoclit, all recognized by Hallier, were gradually abandoned; none was recognized by O’Donell in his various publications (O’Donell 1959a, b) although Mina is still occasionally accepted (Deroin 2001). Within the Argyreieae there has been uncertainty about the limits of various genera, notably Rivea and Turbina, the latter reincorporated in this subgroup and unique for its nearly pantropical distribution. A new genus, Paralepistemon was established to include two African species with thickened filament bases. (Lejoly and Lisowski 1986). In passing, it should be noted that a rather eccentric attempt to reclassify Convolvulaceae by Roberty (1952, 1964) has been universally rejected, like a similar earlier attempt by Rafinesque (1837, 1838a,b).

Recent phylogenetic studies point towards the acceptance of a broad concept of Ipomoea to include all Hallier’s Echinoconieae. Initial studies by Wilkin (1999) and confirmed by our own more extensive sampling (Muñoz-Rodríguez et al. 2019) have shown that even when smaller genera recognized within the tribe Ipomoeeae have strong phylogenetic support, they are nested within Ipomoea. Manos et al. (2001) showed that species with spiny pollen split into two major clades, a result confirmed by Muñoz-Rodríguez et al. (2019). One clade consists of species placed in Stictocardia, Rivea and Argyreia together with a superficially heterogeneous group of species from Ipomoea and Turbina, composed mainly (but not exclusively) of Old World species. The second clade consists of mostly (but not exclusively) New World species but includes Astripomoea, some species hitherto treated as Turbina and all Australian endemics we have sampled. Neither clade can be diagnosed by specific morphological features and it seems that there are multiple origins for many of the characters in Ipomoea including both the capsular and indehiscent fruit types as well as the different number of ovary cells, many characters thus being homoplastic. It is clear from these studies that Ipomoea as hitherto understood is not monophyletic and an expanded circumscription of Ipomoea is required to secure its monophyly (Stefanovic et al. 2003).

Our own extensive studies (Muñoz-Rodríguez et al. 2019) confirm earlier papers and support an Old World origin of Ipomoea s.l. They indicate that the recognition of a broad Ipomoea based on the presence of spiny pollen is the only logical solution that integrates monophyly and diagnosability. The alternative of dividing the whole clade into many small, formally recognized groups is not recommended due to high levels of homoplasy, lack of diagnostic characters and a complex tree model in which it is not obvious to which clades some species, not sampled for molecular data, should be placed. Consequently, we are adopting a wide concept of the genus to include Argyreia, Astripomoea, Blinkworthia, Lepistemon, Lepistemonopsis, Rivea, Stictocardia and Turbina, which are all nested within Ipomoea. However, as the genus is so large, we informally recognize certain diagnosable clades within Ipomoea to facilitate discussion and reflect the phylogenetic history of the genus. These informal clades include some traditionally recognized genera as well as newly discovered groups that contain similar looking plants and are geographically coherent. Where we have recognized informal taxa, we have been as explicit as possible about what species belong to those clades.

Infrageneric classifications

An inevitable result of the situation described in the previous paragraphs is that all existing infrageneric classifications of Ipomoea are to a degree unnatural and many subgroups are neither monophyletic nor well-defined, something that goes far towards explaining the instability of all previous infrageneric classifications.

Choisy (1845) divided Ipomoea into groups based on habit but, while superficially practical, this is clearly artificial and so has only been occasionally and partially adopted by subsequent authors, such as Meisner (1869) and Matuda (1964, 1965, 1966a,b). Grisebach (1862b) reincorporated Quamoclit, Calonyction and Pharbitis into Ipomoea as sections and this treatment was followed by Bentham in Bentham and Hooker (1876), although these authors also incorporated other elements such as Aniseia Choisy within Ipomoea. Clarke (1883) followed Grisebach but treated the sections as subgenera. Hallier (1893b) began the introduction of a hierarchy of infrageneric taxa by recognizing subsections as well as sections and this process was continued by House (1908b), who multiplied the number of subsections. There was then a lull in attempts at an infrageneric classification of American species (O’Donell (1941 and passim) appears to have had no interest) until a major reformulation was made by Austin (1979, 1980), who recognized an even more extensive hierarchy with sections, subsections and series. Austin’s work culminated in a detailed and very complex hierarchical classification published 16 years later (Austin and Huáman 1996).

Apart from the repeated changes of status that these infrageneric taxa have undergone resulting in many groupings being re-graded from subgenus to section to series, the increasing multiplication of infrageneric taxa illustrates the difficulties of achieving a satisfactory classification. Apart from Quamoclit, Pharbitis, Calonyction, Old World Astripomoea and eventually Batatas (Austin 1975a, 1978b), none of these groupings are entirely natural, not even Stictocardia or Arborescens (McPherson 1981), both of which comprise a diagnostic and readily identifiable core of species but with a varying number of other heterogeneous elements. The essential instability of these classifications is well illustrated by the history of series Anisomeres. This was recognized by Austin and Huáman (1996) as a distinct series but was discarded a year later in a paper dissolving the Anisomeres series (Austin 1997). We believe that any attempt to provide a subgeneric classification following a traditional Linnaean model is bound to be artificial, impractical and doomed to failure (Carine and Scotland 2002).

Species delimitation

The history of species recognition in Ipomoea is somewhat chequered. Good taxonomic decisions always require an awareness of previous publications as well as a good understanding of the relative value of different taxonomic characters. Access to a good range of specimens and images as well as field knowledge are also useful but only a few taxonomists have been able to benefit from these. Most have worked with limited material. The new species of early authors have not always stood the test of time (Wood 2017). However, amongst those publishing a significant number of new species of neotropical Ipomoea, it is clear that both Desrousseaux and Kunth demonstrated a high degree of competence, avoiding excessive duplication of names and so most of their species have endured.

The legacy of the most important 19th century expert on Ipomoea, the Swiss botanist Choisy, is very mixed and he was criticised even during his own lifetime. He saw a wide range of specimens in many European herbaria and was well aware of previous publications, but neither his generic nor his species concepts have lasted well. He described the same species under different names often in different genera (Choisy 1845). Ipomoea indica was described under at least eight different names, mostly in Pharbitis and I. batatas under at least four names in Batatas but also in Ipomoea. Similarly I. asarifolia was described under three names in Ipomoea, I. eriocalyx twice, once in Pharbitis once in Batatas, I. delphinioides three times in Ipomoea and so on.

The next major work was the account of Convolvulaceae prepared by Meisner (1869) for the Flora Brasiliensis and this was virtually a monograph of the family in South America. It was as unsatisfactory as Choisy’s works but for different reasons. Meisner appears to have largely discounted the names of earlier authors including those of Choisy. He superfluously redescribed species as if earlier publications did not exist - Ipomoea chrysotricha Meisn. instead of I. hirsutissima Gardner, I. obtusiloba Meisn. and I. heterotricha Meisn. instead of I. bonariensis Hook., I. riedelii Meisn. instead of I. batatoides Choisy, I. graminiformis Meisn. instead of I. schomburgkii Choisy, I. llaveana Meisn. instead of I. funis Schltd. & Cham., I. cardiosepala Meisn. instead of I. philomega (Vell.) House) and many others. The other major problem with his approach was the recognition of a large number of varieties under each species, a process that tended to obscure the boundaries of recognized species. These varieties often recognize trivial variation but, in contrast, in other cases treat distinct, often very distinct, species as mere varieties of unrelated species.

The inadequate species level taxonomy of Choisy and Meisner was not an inevitable consequence of the epoch in which they worked. Near contemporaries such as Grisebach (1862a, b, 1879) or Gray (1878, 1886 were far more reliable. However, the excessive recognition of varieties continued to bedevil species level taxonomy into the 20th century in the publications of Kuntze (1891, 1898), Hallier (1899c) and especially of Chodat and Hassler (1905) and Hassler (1911). Hassler took this interest in infraspecific taxa to an obsessive level, providing names for every slight variant found in Paraguay. However, the publications of the North Americans, especially House (1907 and passim), Brandegee (1889 and passim) and Robinson (1891 and passim) saw a welcome decline in the number of described infraspecific taxa associated with the species they described from Mexico. However the new century did not bring a marked improvement in species delimitation. Urban (1902–3 and passim) and Standley (1924 and passim) between them described over 50 new species of Ipomoea, of which only a quarter are recognized today (Wood 2017.

From the mid-20th century onwards, the situation has improved, partly as the result of the outstanding achievement of the Argentinian botanist Carlos O’Donell (1941, 1948a, 1948b, 1950a, 1950b, 1950c, 1952, 1953a, 1953b, 1959a, 1959b, 1959c, 1960). He described 56 species of Ipomoea of which 45 are accepted today, a success rate far higher than that of any of his predecessors (Wood 2017). Almost everything he described from Argentina is still accepted. He did much to rationalize the chaos left by Hassler, sorted out the Quamoclit Clade throughout the Americas and added significantly to our knowledge of Ipomoea in Bolivia, Peru and Brazil. The vast majority of his taxonomic decisions stand today and his judgement in an era before the internet is remarkable.

After O’Donell’s premature death in 1954, there has been a slow but steady increment of new species from the Americas. Isolated species from different countries have been published by various authors but the contributions of Dan Austin and Andy McDonald are the most significant. Accounts of Ipomoea in Panama, Ecuador, Venezuela by Austin (1976, 1982a, 1982b) have provided a framework for the study of Ipomoea in these countries. McDonald (1987a, 1995, 2001) has revised several groups of Ipomoea principally from Mexico but has also contributed with Austin and Murguía-Sánchez to the account in the Flora Mesoamerica (Austin et al. 2012). Other important contributions have been made by Carranza (1998 and passim) on Mexican Ipomoea and Liogier (1955 and passim) on those of Cuba and Hispaniola.

Discovery of Ipomoea species in America

Inevitably the first species of Ipomoea to be recognized and catalogued from the New World were species of economic importance (I. batatas), of horticultural value (I. alba, I. indica, I. nil, I. purpurea), or were widespread conspicuous species of accessible habitats, such as I. pes-caprae, or I. violacea, which grow on seashores. All were known to pre-Linnean botanists and featured in Species Plantarum and other near contemporary works.

Geographically, the first region from where a reasonably comprehensive inventory of Ipomoea emerged was the eastern United States. Nearly all the localized species from this area had been found and described by around 1800, including species like I. pandurata, I. lacunosa and I. macrorhiza. The United States Southwest had to wait until the 1850s after the United States-Mexican war. It was only then that species from this region were discovered, principally by Wright, Lindheimer and Torrey. Most were described a quarter of a century later by Gray (1878, 1886) including I. leptophylla, I. tenuiloba, I. barbatisepala, I. lindheimeri and I. cardiophylla. After the mid 19th century there was little new to discover in the United States, and most (but not all) described novelties were ephemeral, being shown subsequently to be conspecific with earlier species.

The Caribbean had been one of the earliest regions of botanical exploration and many of its endemic species including Ipomoea ternata, I. tenuifolia, I. repanda, I. digitata, I. clausa and I. desrousseauxii were discovered in the 18th century, as both Jamaica and Hispaniola were visited by botanists from different European countries. Cuba was somewhat different. Although Humboldt and Bonpland visited Cuba, they did not find any of its endemic species. A few were discovered by Sagra in the 1840s, but it was only in the 1860s that the rich diversity of Ipomoea in Cuba became known after Grisebach (1862a, 1866) wrote up the many new species found by Charles Wright (the same Wright who had been active in the United States Southwest). In the years after 1870 there was a slow increment of new species from the Caribbean culminating in the collections of Eric Ekman on Cuba (I. baliocalda, I. erosa) and on Hispaniola (I. luteoviridis), although many of his supposed novelties described by Urban (1924a and passim) have proved to be synonyms of other species. The occasional new species has been found since but the inventory of Caribbean Ipomoea is now largely complete.

There were collections from Mexico in the Spanish colonial era but those of Sessé and Moçiño were not published until a hundred years later. Nevertheless, seeds sent to Spain by them and by Née were cultivated in Madrid enabling Cavanilles to describe several attractive and interesting Mexican species including Ipomoea tricolor, I. stans and I. bracteata at the end of the 18th century. The expedition of Humboldt and Bonpland constituted the next step forward in revealing the wealth of Mexican Ipomoea. Ipomoea cholulensis, I. suffulta and I. hastigera were amongst their discoveries, as was I. arborescens, the first tree Ipomoea to be described. During the first half of the 19th century Mairet, Andrieux, Hartweg and others added to the list of species known from Mexico, but the most important advance came with the collections of Galeotti, which greatly increased the number of known species. His discoveries were published in 1845 and included many well-known Mexican species such as I. lindenii, I. minutiflora, I. chenopodiifolia, I. pauciflora, I. suaveolens and I. proxima (Martens and Galeotti 1845).

After 1845 there was a lull in the discovery of new Mexican species for almost fifty years. However, the end of the 19th century proved to be a golden age for botanical exploration in Mexico thanks to a series of collectors mostly from the United States, especially Palmer, Pringle, Purpus, Nelson and Brandegee, and the Mexican-Italian Casiano Conzatti. The number of recognized species doubled during this era. However, these collections did not exhaust the riches of Mexican Ipomoea and the 20th century has seen the regular discovery of new species by collectors from both Mexico and the United States, notably H.S. Gentry, G.B. Hinton and Rogers McVaugh from the United States and the Japanese-Mexican Eizi Matuda. This trend has continued into the new century with at least eight new species described since 2000. It is too early to say whether this trend is ending but it is perhaps significant that rather few new Mexican species has been found during the course of our studies in Ipomoea.

It was mostly during the 20th century that the Ipomoea flora of Central America was discovered and described. Although not as rich as the Mexican flora, there has been a steady increment of new species since the middle of the century including I. chiriquensis from Panama, I. magniflora from Costa Rica, I. riparum from Honduras, I. heterodoxa from Belize and I. steerei from Yucatán, mostly found by North American collectors. However, the inventory of species seems to be nearly complete, since, as with the Caribbean, nothing new has been reported since the turn of the 21st century.

The earliest collections from South America of any importance were made by Ruiz and Pavón in Peru at the end of the 18th century. They noted surprisingly few new species of Ipomoea but amongst them were I. ramosissima. Of far greater importance was the expedition of Humboldt and Bonpland. Having found new species in Mexico they went on to find a series of new species in the northern Andes including I. discolor and I. parasitica in Venezuela, I. capillacea in Colombia and I. abutiloides in Ecuador.

Essentially little more was discovered or described from the Andean region for well over a century apart from a few species from Venezuela (Pittier 1927, 1931), a few from Peru by Weberbauer (Ooststroom 1933), two from Bolivia (Rusby 1896, 1899) and a couple from Argentina (Grisebach 1879, Kuntze 1891).

This situation only changed after the Second World War initially as a result of O’Donell’s short career (O’Donell 1941 and passim). He significantly increased our knowledge of species in the southern Andes, describing at least six new species from Argentina (Ipomoea jujuyensis, I. rubriflora, I. lilloana, I. oranensis etc.) as novelties, two from Bolivia (I. tarijensis, I. suburceolata), two from Peru (I. velardei, I. peruviana), three from Colombia (I. colombiana, I. killipiana and I. reticulata) and one from Venezuela (I. pittieri); these all still recognised. Fieldwork by Danish botanists led to the discovery and description of three new species from Ecuador by Dan Austin. The diversity in Bolivia was, however, only revealed recently (Wood et al. 2015, 2018, Wood and Scotland 2017b), with the description of 21 new species, mostly Andean which took the total number of Ipomoea species known from that country to 109, thus putting it in third place after Brazil and Mexico for the total number of Ipomoea species recorded.

The 19th century, in contrast, was a golden age for plant discovery in Brazil, mostly under the stimulus of the production of Martius’ Flora Brasiliensis. The roll call of collectors finding new species of Ipomoea in Brazil is composed of most famous plant collectors in Brazil in the 19th century. They include the Germans Martius, Riedel and Sellow, the Brazilians Vellozo and Silva Manso, Blanchet and Glaziou from France, Regnell from Sweden, Gardner, Spruce and Burchell from Britain and Pohl from Austria, their achievement commemorated in species such as I. burchellii, I. regnellii, I. blanchetii, I. spruceana and I. pohlii, all still recognized Brazilian species. The result was that by about 1870 our knowledge of Ipomoea was greater in Brazil than elsewhere in South America.

After the publication of Flora Brasiliensis (Meisner 1869), there was lull in the process of discovery in Brazil, which did not really pick up again for more than a hundred years. It has only been since the 1980s that significant numbers of new species have been found and described from Brazil (Austin 1981, Simão-Bianchini and Pirani 2005 Ferreira and Miotto 2011, Vasconcelas et al. 2016, Wood et al. 2017a,d, Wood and Scotland 2017a,b). It is clear that Brazil is the richest country in South America for Ipomoea but it remains the least explored and it is the only country in the Americas from where we would expect significant numbers of new species to emerge.

As in other aspects of its history, Paraguay (and neighbouring parts of Argentina) has followed a somewhat different trajectory. Until the 1870s, the flora of this region was essentially unknown. Then came a publication by Parodi (1877) listing around 15 species of Ipomoea but in the absence of associated specimens, these names cannot mostly be linked to recognized names. Expeditions by Morong and Balansa began to reveal the diversity of Ipomoea in Paraguay, but it was a long-term Swiss resident, Emile Hassler, and Teodoro Rojas, the Paraguayan curator of his herbarium, who really discovered the Paraguayan flora and revealed the number of Ipomoea species in the country. Between them they added some 20 recognised species, all of which are endemic to the region, some extending into nearby parts of Argentina. Those species that were not recognized by Hassler himself were described subsequently by Carlos O’Donell (1948a, 1950b, 1953a), together with a number of species from Misiones and Corrientes provinces in neighbouring Argentina.

Materials and methods


This monograph is based fundamentally on the study of herbarium specimens of Ipomoea informed by observations from morphology and molecular sequence data, fieldwork, photographs and information from literature and individual contacts throughout the Americas.

We have depended heavily on herbarium collections at Kew (K) and the Natural History Museum in London (BM), which together with material at Oxford (OXF) have formed the basis of our study. We have visited various European herbaria including Edinburgh (E), Leyden (L), Paris (P), Madrid (MA) and Stockholm (S) to view their collections of Ipomoea. During the course of visits to the United States we have seen material at (GH) and (A) at Harvard, the New York Botanical Garden (NY), the Smithsonian Institution in Washington (US), the Field Museum (F), Missouri Botanical Garden (MO) and Arizona University (ARIZ), including extensive material from Fairchild in Florida (FTG). Within Latin America, visits have been made to see herbarium collections in Cuba (HACB, HAJB), Mexico (IEB, MEXU), Ecuador (Q, QAP, QCA, QCNE, GUAY, LOJA), Peru (CIP, CUZ, USM), Bolivia (BOLV, HSB, LPB, USZ), Paraguay (FCQ, PY, SCP), Argentina (CTES, LIL) and Brazil (CEN, CPAP, HUEFS, IPA, JPB, MBM, PEUFR, R, RB, SP, UB). Help received from individuals in all these institutions is detailed in the acknowledgements at the end of this monograph. We have also received important loans of material from most of these institutions as well as from G and GOET. Photographs of herbarium specimens have also been a valuable source of information. The most important have been the images of types available through Jstor (, but the websites of CRIA ( and Reflora ( and those associated with herbaria, including ARIZ (SEInet;, B, BR, C, COL, E, F, MO, NY, P, PMA, US and W have all provided valuable information. We have also been sent images of important material from Geneva (G), Turin (TO), St Petersburg (LE), Vienna (W), Göttingen (GOET), Rancho Santa Ana (RSA), Montevideo (MVM) and Cambridge University (CGE). All cited acronyms are in accordance with the Index Herbariorum (

Much of the material we have been loaned has been type material or old or rare specimens and this has had important limitations on our ability to provide complete and accurate descriptions. In particular, details of the habit of many species is missing and can only be inferred. Flower colour has often been lost or modified during the drying process. It is often impossible, or at least undesirable, to dissect corollas, where only one or two are present pasted to the sheet and fragile in nature. Finally, it must be emphasized that the fruit of many species is unknown.

It is important to stress that herbarium specimens are not only a source of basic taxonomic information and an indispensable tool for species delimitation but also an essential resource for phylogenetic, ecological and other information. We have been able to use specimens for DNA sequencing, even from collections over a hundred years old, if they have been rapidly dried and retain their natural colouring. More recent, heat-dried specimens nearly always yield high-quality DNA, but there are striking exceptions, such as specimens of Ipomoea chondrosepala, which have mostly resisted repeated attempts to extract DNA. Specimen labels are another invaluable source of data. They can provide information that is not apparent from the specimen, such as flower colour, habit and size. Label information can also contain information about the general and specific habitat of the plant and can provide important facts about flowering patterns and ecology. We have used all available information of this kind to inform our descriptions and notes.


The first author has had many years of fieldwork during which he has collected Ipomoea. However, it is only since about 2008 that he has made careful efforts to collect, photograph and study the genus. Most of his fieldwork in South America has been carried out in Bolivia but important visits have been made to Argentina with the help of Hector Keller, to Brazil with the help of Luciano de Queiroz and to Paraguay with the help of Rosa Degen. This fieldwork has been very important in enhancing our understanding of the variation in species and in providing details of their habit and habitat. A consequence is that Bolivia is the only country from where we have near complete molecular sampling, a near complete collection of photographs of living plants and a good understanding of the phenology of different Ipomoea species. It is fortunate that there are 109 recorded species in Bolivia making it the third most species-rich country for Ipomoea in the Americas after Mexico and Brazil.


We have also benefitted from observations and in particular images sent to us by individuals over the years. We are particularly grateful to Maira Tatiana Martinez, Alfredo Fuentes, Alexander Parada, Julia Gutiérrez, Modesto Zarate and Daniel Soto (Bolivia), Moises Mendoza and Hibert Huaylla (Bolivia and Brazil), Hector Keller and Keith Ferguson (Argentina), Gilberto Morillo (Venezuela), Regis E. Bastian, Teresa Buril and Ray Harley (Brazil), Mario Giogetta (Bolivia and Argentina), Erin Tripp (Mexico), Jhon Infante Betancour (Colombia), Rémi Girault (French Guiana), Ramona Oviedo and José Luis Gómez (Cuba). We have also benefitted from images of living plants shown on a number of websites, especially Tropicos ( and SEInet.


We have made full use of a wide range of literature as cited in the list of references. This includes regional, national and local floras and checklists (WCSP (1917), for example) as well as taxonomic works. We have consulted field guides and similar works when we have become aware of their existence. They often provide specific habitat and field identification information not readily available elsewhere. We have also made occasional use of information on the internet, but only if it seems reliable. We have scanned literature for examples of illustrations of species to supplement those prepared specifically for this project.

DNA sequencing

Perhaps the most significant element in our methodology has been the integration of morphological and molecular data. During the course of the five years that we have been studying Ipomoea we have been able to sequence 1,560 specimens and approximately 450 species of Ipomoea from all over the world for ITS and two chloroplast markers (matK and trnH-psbA), 3,035 DNA barcode sequences in total (Muñoz-Rodríguez et al. 2019, supplementary data 3–8). A smaller number of 211 selected species were sequenced for 605 nuclear genes and the whole chloroplast genome (Muñoz-Rodríguez et al. 2019, supplementary data 3–8). Figure 1 summarises the results showing the main clades into which Ipomoea divides. We are particularly grateful to Kew and the Natural History Museum in London for allowing us to sequence large numbers of specimens in their collections and it is from these herbarium collections that the main bulk of our sequence data has been taken. We have had permission to sequence selected examples of species from other herbaria including E, L, MA and P and in the Americas from A, ARIZ, F, GH, HUEFS, IEB, LPB, MEXU, MO, NY, US. Obviously, field collections have provided additional samples for sequencing and we are grateful to several botanists for sending us samples including George Staples, Deng Yunfei (SCIB), Moises Mendoza (UB) and Barbara Kennedy (BISH).

Figure 1. 

Cladogram showing the principal clades into which Ipomoea can be divided, the two main clades indicated as OWC (Old World Clade) and NWC (New World Clade). The placement of traditionally recognised genera and groups is shown in the corresponding clade.

Species concept

Nowhere in biology is the disparity between theory and practice more evident than at the level of species. In an influential and widely cited contribution Kevin de Queiroz (2005, 2007) proposed the ‘unified species concept’ to treat existence of species as ‘separately evolving metapopulation lineages’ as the only necessary property of species and that the plethora of species concepts in existence merely represent different lines of evidence relevant to assessing lineage separation. In this way Queiroz (2005, 2007) separated the theoretical idea of what species are from the operational criteria of how to discover them. An important issue for the recognition of species is that as lineages diverge they can become distinguishable as separate species with diagnostic characters of fixed traits. Species can evolve distinctive ecologies and they can pass through polyphyletic, paraphyletic, and monophyletic stages in terms of their component genes. The problem is that these changes do not all necessarily occur, or if they do occur, do not do so at the same time and they do not even necessarily occur in a regular order (Queiroz et al. 1998). What this dynamic system of divergence means is that there is a certain pragmatic and heuristic nature to species delimitation whereby, although the expectation is that many species are clearly monophyletic, there will be other situations where the estimate of the degree of separation comes down to taxonomic judgement. Therefore, in this monograph we consider species to be separately evolving metapopulation lineages and in the discussion that follows we describe the operational criteria we used to infer, delimit and make taxonomic judgements about species boundaries. From experience gained studying Ipomoea we consider that species delimitation is usually relatively straightforward, given a representative sample of specimens and an understanding of the important diagnostic characters in the genus. Thus, a first task is to gain access to a wide range of specimens for comparison purposes, followed by a study of publications by reliable taxonomists who have worked on the genus. At the same time as specimens are studied morphologically, representative leaf samples from each putative species are sequenced for a few DNA barcode markers to provide an independent data source to corroborate or refute a species hypothesis based on morphological analysis or literature sources. Species delimitation is facilitated if DNA sequencing and specimen examination take place nearly simultaneously but this is only possible when DNA samples can be extracted from the available material. Conceptually as discussed above, we follow Queiroz (2005, 2007), whose framework includes the idea that disagreements about the limits of species are especially prevalent in those species at the active interface of speciation. This explains why many species have universally agreed boundaries whereas others are more difficult to interpret. We take the view that, in the context of taxonomy, for those instances where species delimitation is particularly problematic, it is best to flag up the variation, make a pragmatic, discursive and explicit taxonomic decision and move onto those other species delimitation problems that taxonomy can readily solve. This is especially true in large tropical groups such as Ipomoea in which many of the taxonomic problems can be readily solved by having a good sample of specimens combined with good knowledge of the group’s literature and nomenclature. Our view is that species and species delimitation can be viewed as a heuristic allowing an approach to problem solving or discovery that employs a practical method not guaranteed to be optimal or perfect, but sufficient for the immediate goals. To a greater extent than in Convolvulus (Wood et al. 2015), Evolvulus L. or even Jacquemontia, most species of Ipomoea are, as a generalization, well-defined. Hybridization is rarely reported, and that principally in the Batatas Clade. Claims by Austin that I. leucantha and I. grandifolia are of hybrid origin require corroboration. There are, of course, species complexes where delimitation is difficult, as intermediates occur between recognized species and these may be hybrids but a lot of the difficulty faced by the taxonomist arises from the lack of available material for study. Almost 20 species in the following account are only known from the type collection, another 50 or so are only known from less than five collections, and not all of these have been available for study. In about 20 cases, we have not seen authentic material and have relied on images and original descriptions to describe and delimit species. Inevitably, we are tentative in our decisions on the validity of some individual species. Examples include I. leucantha mentioned above as well as several species in Clade A1 (Figure 1; Muñoz-Rodríguez et al. 2019), such as I. vivianae or I. pseudomalvaeoides. A particular case is the pantropical I. indica. Molecular studies show that this is polyphyletic (Muñoz-Rodríguez et al. 2019, supplementary data 3), but it is clear that a more exhaustive study with extensive sampling is necessary before the components of this entity can be unravelled.

We have tried to make use of so-called conservative characters in accepting species and the value of these is discussed in the notes that follow. Pollination syndromes as reflected in corolla shape and to some extent in colouring and the structure of the androecium are seen as important for species delimitation (Rosas-Guerrero et al. 2011). Ideally each species will be delimited by a combination of distinctive characters. Species defined by a single character, unless it is exceptionally strong, are regarded with suspicion. We do take into account ecological and geographical factors. We would expect different species to have different ecological requirements or occupy a different geographical area from obviously related species. Where morphology, ecology and geography intergrade we have indicated by notes and in some cases by the recognition of subspecies. We have used insights from molecular sequence data, keeping separate apparently similar species like I. marginisepala and I. cardiophylla or I. asarifolia and I. paludicola where uniting them would render them non-monophyletic. We have been reassured in our species level decisions by molecular data in the recognition of numerous species, for example, I. huayllae, I. graniticola, I. chiquitensis and I. juliagutierreziae from Bolivia and I. kraholandica and I. chapadensis from Brazil. Molecular data has been less helpful for species delimitation within some of the relatively large clades such as Clades A, 1–2 (Figure 1) where multiple accessions of several species are not resolved partly due to the limited variation provided by regions used.


The concept of a subspecies is retained for taxa which are morphologically distinct throughout most of their range but whose characters overlap in regions where the ranges of the two taxa meet. We accept that some species recognized in the following account could have been treated as subspecies of a closely related species, but in many cases, the number of specimens seen is so few that it would be premature to make this decision. Subspecific status is, therefore, reserved pragmatically for taxa of which we have seen many examples. Subspecies are keyed out when there are three more recognized subspecies for a particular species.


Apart from subspecies, other infraspecific categories are not formally recognized in this account with the exception of two varieties. Most varieties, formas and subformas recognized by previous authors have little value and often do little more than recognize minor variations of corolla colour, indumentum or leaf shape. Some varieties, however, have long been recognized and, where these are historically significant or readily recognized, we have drawn attention to them in the notes that follow the species descriptions and made comments about their distinctive characters and distribution. We accept that some readers may wish to continue recognizing and using these varietal names. We understand varieties as morphologically distinct populations that occur sporadically over part or all of the range of a species. Although varieties may be restricted to a specific area they do not occupy a distinct geographical region with populations overlapping with those from another distinct geographical area. Sporadic occurrence is an important criterion in the recognition of varietal, rather than subspecific status.

Structure of the monograph

In the following taxonomic account species are arranged in a linear order, reflecting phylogenetic relationships as far as is possible (Muñoz-Rodríguez et al. 2019). The 605 nuclear regions we sequenced provided an overall framework for the major clades we recognise but as the number of sequenced species was relatively small, this provided information on the placement of only about 140 species from the Americas into major clades. We have added to this analysis with information from chloroplast sequences and ITS, thus increasing the coverage to well over half the American species. Where there were differences between nuclear and chloroplast results we generally followed the nuclear data because of the larger data set and the support it gave for major clades. In cases of incongruence (Ipomoea parasitica, for example) we considered the size and increased support offered by the NGS nuclear data to be more reliable than ITS (Muñoz-Rodríguez et al. 2019). The order of species was then expanded based on obvious morphological similarities, thus all species in the Quamoclit Clade were grouped together as were all the inferred relatives of I. malvaeoides, even though we had not obtained sequences for some species in these groups. There remained a residue of species (± 40) whose placement was somewhat arbitrary as it was based on uncertain interpretation of morphological characters. Only five species are included at the end of the treatment as we were unable to suggest any likely placement.

The process described above was not always straightforward as the resolution of some parts of the phylogeny is poor, particularly in Clade A (Figure 1, Muñoz-Rodríguez et al. 2019). Nevertheless we are confident that the order of species presented in this monograph is a reasonable approximation reflecting the phylogenetic history of Ipomoea (Muñoz-Rodríguez et al. 2019).

The accepted names of species and subspecies are given in bold italics, followed by their author and place of publication. Where a recognized taxon is based on a nomenclatural combination, the basionym is given in plain italics immediately following the accepted names. This is followed in chronological order by any other names based on the same basionym. Heterotypic synonyms are then listed in chronological order of their basionym, each followed by subsequent combinations based on each basionym. Finally any commonly used name misapplied to the species is listed but only very common misapplications are cited. Authorities are not cited in the notes and other discussion sections for taxa that are treated in the monograph unless needed to clarify some typification or nomenclatural issue.

Types are cited for all listed taxa. The location of all types is indicated by the appropriate acronym following Index Herbariorum (, the only exception being CIP (Centro Internacional de La Papa at Lima), whose herbarium is not included in Index Herbariorum but does contain some types. We have tried to indicate the holotype (or lectotype) in each case and we have seen all holotypes and lectotypes unless indicated with n.v. (not seen). We have not necessarily seen all isotypes but have listed herbaria where they are reported to be present. The list of isotypes may not be complete in every case and we have uncovered numerous isotypes during the course of our visits to different herbaria. Many more are likely to be found in herbaria we have not visited. We have designated lectotypes in many cases where no holotype existed or where it was ambiguous. It is hoped this will help achieve nomenclatural stability.

Descriptions all follow the same sequence and should be comparable although some details (fruits and seeds for example) are not always known. Subspecies are treated diagnostically following the main species description. With two exceptions varieties are not formally accepted and are included within the synonymy of individual species. However, those varieties we consider particularly significant are highlighted in bold in the notes that follow each species and we indicate what their distinctive characteristics are.

References are provided to illustrations after the descriptive text. These include all illustrations in the present work and selected illustrations from other publications. We have only selected illustrations from relatively recent publications with an emphasis on those from publications related to the Americas. However, we have included references to Bosser and Heine’s (2000) Flora of the Mascarenes and Deroin’s (2001) Flore de Madagascar 2001, although these works are not American, The two floras have illustrations of outstanding quality, showing most of the widespread species and including details which are not shown in other drawings. Systematic references to photographs have not been made. These are increasingly available on websites such as Tropicos, Reflora, SEInet and those of individual herbaria and on the websites of individual research workers.

Geographical information is provided country by country. Continental countries are ordered from south to north as follows: Eastern non-Andean, South America: Uruguay, Argentina, Paraguay, French Guiana, Surinam, Guyana; Western South America northwards, Chile north to Venezuela and then northwards from Panama to Canada. The islands are ordered from Bermuda to Bahamas, Turks and Caicos, Cuba, Cayman Islands and Jamaica, then from Haiti in an arc east and south to Trinidad, with the Netherlands Group at the end. Hawaii is placed in final position. Although apparently rather eccentric, this order ensures to a very large extent that plants whose range extends into adjacent countries or along mountain or island chains are arranged into logical distribution patterns.

Citations of occurrence are provided for all countries and, where possible, for major areas (states, provinces or departments), highlighted in bold face, in the larger countries. All South American countries except Uruguay and the Guianas are treated as “large countries”, together with Mexico, the United States and Canada. Major areas within larger countries are arranged alphabetically. The small Caribbean islands are treated as “major areas” of the Lesser Antilles. Citations are based on specimens seen or, in a few cases, identified by an established authority who is known to have understood the species well. Records from checklists and, especially data bases without images, have not been used as they contain many errors (Goodwin et al. 2015) and, if included, are indicated with the word fide. As a general rule at least one specimen is cited for every country and major area in larger countries. The purpose of the citations is to provide evidence of the presence of a species in a particular territory, not to provide a complete list of specimens seen, but in the case of rarer species, all specimens we have seen may be cited. If a user of this monograph wishes to confirm a record this can be traced through the cited herbarium. Photographs of many but not all cited specimens are available on line through the web sites of the relevant herbaria. Many individual records can also be traced through our project website “”.

Ecological information is included within distributional information. Our knowledge of the ecology of individual species varies from zero to good. It is particularly poor in cases of very localized species. Many of the widespread species occur as garden escapes, weeds or adventives in and around settlements and by roads. The only Ipomoea species reported to be invasive is I. aquatica and that only in Florida and Cuba. No troublesome weed of cultivation has been noted.

Explanations for lectotypifications are provided separately from other notes. In cases where no explanation is provided, it should be assumed that the most complete specimen seen and cited by the original author was chosen.

Notes are mostly related to taxonomic issues. They often summarise distinctive characteristics of a species and indicate how it can be distinguished from other species with which it is often confused. Some information has been given about traditional and economic uses but this has not been a focus of attention in this monograph.


Molecular sequence data

Results from molecular sequencing and phylogenetic analysis have been of great value in our research at many levels (Wood et al. 2015; 2017a, b, d; 2018) and have enabled us to delimit Ipomoea as a genus, facilitating the study of its evolution (Muñoz-Rodríguez et al. 2018, 2019). It has enabled us to recognize major radiations in South America within Clade A1 (Figure 1) and in the Caribbean within Clade A2. It has confirmed the monophyly of some groups previously recognized on morphological grounds, such as Calonyction, Quamoclit, Astripomoea and Batatas (Muñoz-Rodríguez et al. 2019, supplementary data 3–8). Other accepted groupings, such as Argyreia, Pharbitis, Stictocardia and the Arborescens group are shown only to be monophyletic if certain species are excluded. Conversely, it has demonstrated that some recognized groups are not monophyletic (Turbina for example) and that Rivea is nested within Argyreia. Importantly the phylogenetic framework we have developed provides a context in which to interpret and understand the evolution of the many species of Ipomoea that lay outside the previously recognized segregate genera.

DNA sequencing and phylogenetic analysis has been valuable at the species level too. It has confirmed the monophyly of many species and has also drawn attention to the existence of unrecognized new species. We have many examples of this, such as the “discovery” of Ipomoea kraholandica in Brazil or I. lactifera in Bolivia, this last especially interesting as DNA confirmed it as belonging to the Batatas Clade and sister to the Old World species, Ipomoea littoralis. Sequence data has shown some species thought to be distinct are conspecific with others from different geographical areas, for example, I. acanthocarpa from Africa is the same species as I. piurensis from America, while I. lindenii from mainland America is the same as the Jamaican endemic I. cyanantha. In both these examples multiple specimens of the supposedly distinct species form a largely unresolved single clade confirming our morphological observations that the species are indistinguishable. DNA has also demonstrated that some species pairs thought to be possibly conspecific are indeed different; I. paludicola is distinct from I. asarifolia, I. marginisepala from I. cardiophylla and I. pterocaulis from I. jalapa. In these examples specimens from the two species do not form a clade separate from all other species. DNA has also shown that Ipomoea indica is not monophyletic and so consists of more than one entity, although we have not yet been able to unravel this complex. It has highlighted misidentifications when wrongly named specimens appear in parts of the tree separate from the clade where they belong. It has also provided a phylogenetic context to enable the interpretation of incomplete specimens, which lack diagnostic morphological information. However, molecular sequencing using ITS has severe limitations which are well documented, not least lack of resolution and support. For this reason, we have always used our ITS phylogeny in conjunction with hypotheses based on morphological characters. Nevertheless, we have been reassured that all major clades identified in our ITS tree are also inferred from the analysis of single-copy nuclear regions and of whole chloroplast genomes (Muñoz-Rodríguez et al. 2019).

Major clades of Ipomoea

Figure 1 summarises the phylogeny of Ipomoea and shows the genus is divided into two clades of similar size. These are labelled for ease of reference but are not formally recognized. The two clades are dominated by species from the Old World and New World respectively but with many exceptions. The Old World Clade (OWC) consists of species previously placed in Argyreia, Rivea, Stictocardia and Lepistemon as well as many always included in Ipomoea. The New World Clade (NWC) consists of an early diverging grade of Old World elements and a species-rich clade dominated by species from the Americas, but which also includes all species endemic to Australia. The existence of this fundamental split within Ipomoea had been posited by previous research (Miller et al. 1999 Manos et al. 2001) although based on much poorer taxon sampling.

Both NWC and OWC contain elements that were recognized previously as genera and appear as smaller clades within NWC or OWC. The only previously recognized genus that is represented by native species in both NWC and OWC is Turbina, although most of its species are in OWC. Turbina is polyphyletic containing several heterogeneous elements and is consequently rejected. Similarly, we reject the New World genus Exogonium as it was founded on a hypocrateriform corolla adapted for bird pollination and this character is homoplastic occurring in various different clades within NWC. In NWC, species formerly grouped under the names Arborescens, Batatas, Pharbitis, Calonyction and Quamoclit all form small clades which more or less coincide with their traditional circumscription and so are used by us as names for the corresponding clades. In OWC the generic names Argyreia, Astripomoea, Stictocardia and Lepistemon form clades of varying sizes and we continue to use these names for these distinct clades. Unlike the New World clades recognized above, these Old World clades vary considerably in size, Argyreia having around 125 species (including Rivea), Stictocardia around ten and Lepistemon only two so barely meriting recognition. All these nine clades which are assigned traditional names are more or less diagnosable using combinations of morphological characters.

NWC comprises about 450 species. Apart from a few species previously placed in Turbina, all species belong to Echinoconieae subgroup Ipomoeeae in Hallier’s (1893a, b) classification. Most (All?) Australian endemics belong to this clade and it is also well represented in Africa. Within NWC, two very large clades are recognizable. One clade (mostly South American but including Batatas) roughly coincides with subgenus Eriospermum (Hallier f.) Verdc. ex D.F. Austin as defined by Austin and Huáman (1996), although Austin included many elements which do not belong, such as Ipomoea rubens, I. lindenii, I. violacea, I. imperati, I. magnifolia, I. habeliana etc. (Muñoz-Rodríguez et al. 2019). We refer to this as Clade A. There is a second very large, mainly Mexican, clade that has not previously been recognized which includes Austin’s subgenera Ipomoea and Quamoclit as well as some other species. We refer to this as Clade B. Clades C, D, E and F represent smaller clades within NWC, this last essentially African with one New World endemic (I. habeliana).

Our studies have revealed many smaller clades to which a traditional name cannot be readily attached. The two largest are both in Clade A of NWC and we refer to these as Clades A1 and A2. Some of the species in Clade A1 were treated as series Jalapa by Austin and Huáman, but in a very inconsistent way. It is found throughout the neotropics but is most diverse in South America. The Arborescens group form a small clade within A1. Clade A2 is also found throughout the neotropics but is particularly important in the Caribbean, as nearly all the 25 endemic species of that region belong to it. Elements of this clade were referred to as Microsticta by McPherson (1980) and as series Eriospermum by Austin and Huáman (1996). Both Clade A1 and Clade A2 are usually recognizable morphologically, the former by its pubescent corolla and rather soft, flattish sepals and the latter by its usually glabrous corolla and coriaceous, often convex, ovate to elliptic sepals. We note that there are a few exceptions in both these clades and that several of these diagnostic characters are homoplastic in other parts of Ipomoea. Clade A3 is a small clade comprising the Batatas group. Ipomoea cryptica is sister to this clade in the nuclear phylogeny but not in the chloroplast phylogeny.

Apart from Pharbitis, Calonyction and Quamoclit, there are several small clades which are more or less diagnosable morphologically within Clade B. There is a small clade (Species 328–334) of seven species centred on Ipomoea costellata assigned the name Pedatisecta by House (1908b) characterized by digitately divided leaves. These were treated as part of Sect. Leptocallis by McDonald (1995) but the name Leptocallis has to refer to a quite different small clade (Species 280–288) centred on I. capillacea, perhaps characterized by tuberous storage roots. The most distinct small clade in Clade B consists of five species characterized by pinnatifid leaves and centred on I. stans (Species 275–279). These were included in Sect Tyrianthinae by McDonald (2001) but this name cannot be used for this clade as the type, I. orizabensis, belongs to a different clade. Since the six small clades discussed here account for only a small proportion of the species in Clade B, we have avoided any formal recognition of these names.

Clade C also contains a number of small clades which are more or less diagnosable morphologically or geographically, although the best known species, Ipomoea pes-caprae, belongs to a clade of Australian species. A small clade of four species (Species 345–348) centred on I. asarifolia can be recognized by their very unequal, transversely muricate sepals. Another small clade of South American species consisting of perhaps eight species centred on I. maurandioides (Species 356–363) that can be recognized by their glabrous indumentum, unequal sepals and often trailing habit.

The Old World Clade (OWC) contains around 350 species mostly from the palaeotropics. It includes most species treated as Echinoconieae subgroup Argyreieae by Hallier including all species placed in Argyreia, Rivea (which is nested within Argyreia), Stictocardia and some species placed in Turbina. Only a few relatively small clades are composed of neotropical species. Much the largest is the clade of around 12 species centred on I. corymbosa but with morphologically very disparate elements, including I. ochracea, I. regnellii, I. crinicalyx, I. cuscoenesis and I. daturiflora.

There are important practical implications from our molecular results. Since there is no obvious or close correlation between morphological characters and the Ipomoea phylogeny, it is currently impossible to propose an infrageneric classification along traditional lines. Although most clades cannot be defined morphologically, they do have certain morphological tendencies, which we have highlighted and discussed in the notes that precede the description of the species in each clade. As noted above, some of the smaller clades are well-defined and, where this is the case, their distinctive morphological features are indicated. We have also tentatively used molecular results to inform the placement of individual species within clades.

It should be stressed that we have faced a problem that we share with previous botanists working on the classification of Ipomoea. Some species are not available for study or sequencing and so cannot be assigned unequivocally to a clade. In this situation, we have inferred the position of species from their morphology. Most placements will be uncontroversial but in a few cases they are little more than guesses. The notes following each species indicate where placement is particularly uncertain.

Geographical distribution

Ipomoea is a tropical genus and this is reflected in its distribution in the Americas with few species found north or south of 30 degrees latitude. The main exception lies in the Eastern United States where several species, I. coccinea, I. lacunosa, I. sagittata and I. pandurata, extend north to at least 35 degrees, I. repanda as far as 43°N in Ontario, Canada. The complete absence of Ipomoea from California in the west apart from a few introduced ornamentals (as well as in central Chile) suggests that it cannot tolerate a Mediterranean climate with arid summers and cool wet winters.

Within the neotropics Ipomoea is widely distributed but is noticeably less diverse in the equatorial region with relatively few species in Amazonia, Ecuador (Austin 1982a) or Colombia (Bernal et al. 2015). Although a partial explanation lies in the low diversity of Ipomoea species generally in rain forest, it does not account for the lack of species diversity in the dry forests of the Caribbean coasts or of the inter-Andean valleys such as the Colombian Magdalena. Species diversity rises as one moves away from the Equator and the countries with the greatest diversity of species lie mostly within the 15 to 30 degrees of latitude, notably Mexico and Brazil, both large countries with extensive subtropical dry forest. Some smaller countries in these latitudes, such as Paraguay (Wood et al. 2017c), Bolivia (Wood et al. 2015) or Cuba (Wood and Scotland 2017c) are proportionately as rich.

Most species of Ipomoea are relatively localized in their distribution often being found in a single region or country. However, there is a large set of species (I. alba, I. batatas, I. cairica, I. carnea subsp. fistulosa, I. corymbosa, I. hederifolia, I. indica, I. muricata, I. nil, I. purpurea, I. quamoclit and I. tricolor) that occur around cultivation or in disturbed places near settlements throughout the tropics and are found in almost every country of the Americas with a tropical climate. To this group should be added some other pantropical species that are also widespread but absent from many countries including I. acanthocarpa, I. aquatica, I. asarifolia, I. fimbriosepala, I. mauritiana, I. setifera and I. triloba. All these pantropical species occur sporadically, occasionally abundantly, in different neotropical countries but there is little geographical patterning to their distribution. A similar pattern can be observed in the palaeotropics. Of the 26 species recorded for the Flora of the Mascarenes (Bosser and Heine 2000 all but one also occur in the Americas. Equally all but two species recorded from Hawaii are also present on the American continent.

Of species never found in the Old World, Ipomoea aristolochiifolia is probably the most widespread, being found from Argentina north to Mexico, although it is absent from the Caribbean islands. Other very widespread species include I. philomega, I. batatoides, I. ramosissima and I. regnellii but, apart from I. ramosissima, none extends into Argentina and all peter out as they enter Mexico. Two species, I. dumetorum and I. clavata extend along the Andean Chain from Argentina or Bolivia north to Mexico but are absent elsewhere. More frequent are species that extend from the United States or Mexico southwards to northern South America. These include I. capillacea, I. cholulensis and I. lindenii that are restricted to the mountain chains and I. minutiflora, I. meyeri, I. trifida and I. tiliacea which are common in the Caribbean (except I. minutiflora) and Central America extending into northern South America, in the case of I. tiliacea south along the eastern edge of Brazil almost to Uruguay. Of some interest are two upland species, I. plummerae and I. pubescens, common around the 20–30° latitude in both hemispheres but largely absent from intermediate equatorial regions.

Ipomoea plummerae and I. pubescens are not the only species with disjunct distributions. Ipomoea crinicalyx and I. amnicola are also amphitropical in distribution but there is suspicion that the latter has been introduced into the northern hemisphere. Several annual species like I. parasitica, I. heptaphylla, I. longeramosa and I. neurocephala are very scattered in their distribution, being known from many countries but, with the exception of I. longeramosa in NE Brazil, from only one or few collections in each case. The occurrence of the South American I. subrevoluta on the Isla de Juventud (Pinos) in Cuba and also on Trinidad is remarkable but it perhaps arrived as a result of the movement of migratory water birds. Ipomoea thurberi also has a curious distribution with isolated populations in Guatemala and Nicaragua which are disjunct from each other as well as from the main population in northern Mexico and Arizona. In South America remarkable disjunctions are noted for species found on isolated granite domes around the Amazon. Ipomoea chiquitensis and I. graniticola are known from a few locations separated by many thousands of kilometres (Wood et al. 2017c). The apparent disjunctions in the distribution of two species found in the Amazon basin, I. amazonica and I. velutinifolia can be explained by inadequate collecting in areas separating known locations. The most inexplicable disjunction, however, is that of I. eremnobrocha known from the Cerro Campana in Panama and from a number of locations in NE Brazil.


Throughout the Americas many species are endemic to single countries with a good number of species endemic to single localities or to a very restricted area. Clearly the two largest countries, Brazil and Mexico, each with about 60 endemic species, have the greatest numbers of single country endemics. Scattered endemic species are found in most Andean countries with much the greatest numbers in Bolivia (c. 20) but the arbitrary nature of political boundaries tends to reduce the gross figures for individual countries. There are few species endemic to the small Central American republics although four are endemic to the Panama-Guatemala region. The large Caribbean islands are also major centres of endemism. We recognize 17 species as endemic to Cuba, seven to Hispaniola and four to Jamaica. Additionally there are a number of near endemics on these islands. In contrast, species endemic to small islands or island groups are few and we recognize only four, Ipomoea sphenophylla on St Eustatius, I. steudelii on Puerto Rico, I. tuboides on Hawaii and I. habelana on the Galapagos, the last two on several islands in their respective archipelagos and, perhaps coincidentally, both adapted for moth pollination.

It is harder to discern concentrations of endemic species in particular regions of the large continental countries, particularly in Mexico, where endemic species occur in scattered locations over much of the country. However, there is evidence that the greatest concentrations of endemics are in the seasonally arid regions of South West Mexico (McDonald 1991), with a lesser centre in the central northern plateau. Much the same is true for South America but the Chapada de Veadeiros (Brazil) is home to at least four endemic species and the Sierra de Amambay (Paraguay) to at least three. Both these locations are also home to several other very rare species which extend only to a few nearby locations. Another very rich area comprises the lower eastern slopes of the Andes near the border of Argentina and Bolivia. This is exceptionally diverse in terms of local endemic species with at least nine species endemic to the area.

It is equally difficult to discern clear examples of endemism in particular biomes except for some extreme examples such as seashores. Clearly there are many species endemic to Seasonally Dry Forest and to Cerrado but as the former includes many distinct variants and the latter very different physiognomies from campo limpo to cerradão, the notion of endemism is not very easy to apply except in a very loose sense. Specific examples of habitat preferences are indicated after species descriptions, where these are reliably known.


Precise information about the ecology of many species is unavailable so it is difficult to provide anything approaching a comprehensive account of the habitat requirements of many neotropical species. Certainly, Ipomoea species grow in many different habitats and it is clear that most habitats host species specific to that habitat.

The most typical beach species are Ipomoea pes-caprae, I. imperati and I. littoralis (in Hawaii) but others occur on coastal sands including I. tiliifolia and some forms of I. batatas. There is some evidence that the fruits of some of these species can survive for long periods in salt water (Miryeganeh et al. 2014) and it has been suggested that in the case of I. pes-caprae the persistent pedicel actually aids seed dispersal. The world distribution of these species and that of I. violacea, which often grows in mangrove swamp, strongly suggests that their dispersal is mediated through ocean currents. This may be the explanation of how the salt marsh species, I. sagittata made it to Europe in prehistoric times. Ocean currents may also partially explain the distribution of Ipomoea indica and I. triloba as both show a predilection for islands, although the former is also readily spread by broken shoots as a result of trampling by cattle. There is also an interesting group composed of species that are not strictly maritime but are often found in the proximity of the coast, although all occur, sometimes abundantly inland; these include Ipomoea tiliacea, I. mauritiana, I. digitata, I. asarifolia, I. macrorhiza and I. jalapa.

Some species are characteristic of freshwater habitats and are often specialized in their requirements. The only true aquatic is the introduced Ipomoea aquatica, which roots on mud and sometimes has extensive floating stems. Ipomoea subrevoluta usually grows by small streams in grassy plain whereas I. rubens is more typical of the borders of larger rivers or small lakes. Ipomoea paludicola, I. schomburgkii and I. pittieri favour flooded pampa whereas I. paludosa is characteristic of swampy hollows in the cerrados. Ipomoea fimbriosepala, I. setifera and I. neei are often found near water. The widespread species I. alba appears to favour disturbed scrubby gullies which are permanently or seasonally moist, when it grows as an apparently native species. The natural distribution of I. carnea subsp. fistulosa is obscured by its presence as an escape from cultivation but it appears native in swamp in the Parana basin of South America and perhaps elsewhere.

The lack of diversity of Ipomoea in rain forest does not mean that there are no characteristic species in this habitat. The best indicator of rainforest in the genus is I. philomega, which is found in evergreen forest at low altitudes throughout the Americas. Other typical species that are more local in their distribution include I. amazonica, I. velutinfolia, I. santillanii, I. splendor-sylvae whereas I. aurantiaca, I. chondrosepala, I. regnellii, I. squamosa, I. batatoides and I. reticulata also occur in rainforest but are not restricted to this habitat. The near absence of several otherwise widespread species from the Amazon basin is also interesting. Ipomoea hederifolia and I. carnea subsp. fistulosa are almost completely absent from Amazonia.

Cloud forest is another wet forest habitat where Ipomoea is relatively poorly represented. Cloud forest occurs from slightly below 1000 m to at least 2500 m along the Andes from Bolivia northwards, in the Brazilian Atlantic forest and in Central America. Probably the most widespread cloud forest species is I. lindenii, which grows from Bolivia to southern Mexico with an outlying station in Jamaica. Other cloud forest species are much more local but include I. austrobrasiliensis from the Brazilian Atlantic Forest, I. magnifolia, I. inaccessa and I. odontophylla from the Bolivian Andes, I. retropilosa from Colombia and Venezuela, I. chiriquensis, I. isthmica from Panama and Costa Rica and I. chenopodiifolia from Guatemala and Mexico. Other species may occur in coffee plantations, which are often created from areas of former cloud forest including the widespread I. aristolochiifolia.

High altitude species are even rarer and very few species occur above about 2500 m. The only species that might occur in paramo is Ipomoea capillacea while, in puna or at least subpuna, the only species recorded are I. plummerae and I. pubescens. Both have a disjunct amphitropical distribution occurring in Mexico and the United States Southwest as well as South America. Ipomoea plummerae reaches 4000 m in Bolivia.

Ipomoea species are tolerant of drought and several are recorded from desert. In South America I. incarnata is the best adapted to arid conditions occurring in the coastal deserts of Peru and the Colombian Guajira as well as the Caatinga of NE Brazil. Other indicators of very arid conditions in South America are I. nationis from Peru, I. verruculosa from Venezuela and I. sericosepala from Brazil and Bolivia. In North America, Felger et al. (2012) record some 13 species from the Sonora desert region of Mexico-Arizona, listing I. cardiophylla, I. costellata, I. cristulata and I. ternifolia as typical of this habitat. Most tree species from the Arborescens clade in both South and North America favour arid habitats but are more typical of dry deciduous forest than true desert.

Of some interest are morphological adaptations found in several species growing in dry habitats. One such occurs in the coastal lomas of Peru and the northern Atacama of Chile. Here forms of Ipomoea dumetorum, I. nil and I. purpurea occur with short, erect stems, very unlike the normal long twining stems found in other habitats. The Galapagos Islands comprise another arid habitat where there occur extreme forms of I. muricata and I. incarnata, once treated as distinct species under the names respectively of I. tubiflora and I. linearifolia. In the former the fleshy teeth of the stems are largely suppressed while the latter presents with very narrow leaves. In the Sonora Desert in Mexico, forms of I. cristuluta occur with erect, woody virgate stems, a facies very different from the normal herbaceous, twining stems. Perhaps the most remarkable is the dwarf form of the usually lowland I. platensis which grows in arid situations at over 2000 m in the Argentinian Andes. (Figure 83).

Desert merges into dry grassland, particularly in North America. Erect and, less commonly, trailing species of Ipomoea are characteristic of grassland habitats. There are relatively few examples from North America, I. leptophylla being the only widespread prairie species but several other North American species are clearly adapted to the grassland habitat, including I. longifolia and the Mexican endemic I. durangensis. However, it is in the South American cerrados that a great number of grassland species have evolved. Erect species occur in different clades and include I. hirsutissima, I. malvaeoides and I. cuneifolia and several others from Clade A1, I. argentea and I. paulistana from Clade A2 and I. squamisepala and I. pinifolia from Clade C. Trailing species are also common including I. descolei, I. psammophila and I. langsdorfii, I. burchellii, I. goyazensis and I. procumbens.

Thorn scrub merging into seasonally dry forest is another important semi-arid habitat, which is common throughout much of tropical America. Ipomoea is at its most diverse in this habitat. In South America the relatively widespread species I. amnicola, I. megapotamica, I. incarnata and I. abutiloides are good indicators of this habitat. However, each of these dry forest regions has its own set of localized species, I. argentinica, I. oranensis and I. schulziana where the chaco meets the Andes, I. brasiliana, I. longibracteolata, I. marcellia and others in NE Brazil. Ipomoea verruculosa in the dry coastal woodland of Venezuela, I. pauciflora and I. velardei in Ecuador and Peru. Dry forest species are also noted from the Caribbean Islands, I. carolina from Cuba, for example, but it is in Mexico and Central America that very large numbers are recorded as growing in dry forest, usually pine or oak woodland, either wholly deciduous or partially so. All the tree species (from both North and South America), lianas like I. bombycina and numerous other species are recorded from this habitat. The roll call of dry forest species from Mexico is long and includes such relatively common species as I. orizabensis, I. pedicellaris, I. praecana, I. seducta, I. lobata and many others.

Ipomoea species tend to avoid closed forest but occur along streams, by tracks and roads and often favour rock outcrops where the forest cover is broken. Species diversity is greatest in deciduous forest, possibly because there is more plentiful light during the dry season (McDonald 1991). This could be an explanation for why some dry forest species flower in the dry season at a time when they are leafless. This is a particular feature of the tree species in general, some Mexican species such as I. tehuantepecensis, I. pseudoracemosa, I. concolor and I. pruinosa, but of relatively few South American species wth the exception of I. juliagutierreziae and I. schulziana.

Rocks provide a specialized habitat for some species. In Mexico, cliffs or “crags” are often cited as the habitat for Ipomoea rupicola, I. chilopsidis, I. teotitlanica, I. seeania and I. concolor whereas in South America the only species cited from a similar habitat is I. killipiana. The geological composition of the cliffs is not usually recorded but volcanic rocks are mentioned for I. seeania and limestone for I. teotitlanica. Limestone, however, is often cited for plants from the Caribbean including I. montecristina, I. praecox and I. fuchsioides from Cuba, the last two characteristic of limestone towers locally known as mogotes. It is also cited for several species from Hispaniola including I. digitata and I. desrousseauxii. Ipomoea luteoviridis is recorded from serpentine outcrops in Hispaniola but we are unaware of any other American species with this habitat preference. A few species are noted from lava flows, notably I. tuboides from Hawaii, but several Mexican species are recorded on pedregales including I. orizabensis and I. dumetorum. In South America the most commonly recorded specialized rock habitat consists of granite domes and platforms, which outcrop sporadically in dry forest and cerrados on the pre-Cambrian shield. The commonest species of this habitat are I. bonariensis and I. maurandioides, but neither is restricted to granite. More restricted geographically and geologically and often very disjunct in their distribution are I. caloneura, I. chiquitensis and I. graniticola, the last being found in isolated locations in Bolivia, Brazil and Paraguay. Ipomoea leprieurii is locally frequent on granite outcrops in French Guiana and neighbouring parts of Brazil while I. marabaensis, I. scopulina and I. fasciculata are currently known only as pin-point endemics.

Ipomoea species are also frequent in secondary scrub and in disturbed places around settlements. This is the kind of habitat where the widespread pantropical species are often found. Ipomoea indica, I. nil, I. hederifolia, I. purpurea and I. cairica are rarely found far away from human habitation and I. alba, I. cairica, I. tricolor, I. indica, I. quamoclit and I. carnea subsp. fistulosa are sometimes clearly garden escapes. The same is true for many species of the Batatas clade. Ipomoea tiliacea, I. triloba, I. cordatotriloba, I. australis, I. leucantha, I. grandifolia and I. trifida are all recorded as characteristic of disturbed bushy ground and are rare in truly natural habitats.


Many species have a distinct, relatively short flowering season. The only country where details are documented, albeit superficially is Bolivia (Wood et al. 2015). Similar details are largely unknown from other countries although information about 12 Mexican species is provided by Chemás-Jaramillo and Bullock (2005). The short flowering season is at least a partial explanation for why some species are rarely collected and so are only known from one or two examples.

Certain generalisations, however, are possible. The erect cerrado and grassland species with a stout xylopodium often come into flower soon after the start of the spring rains, possibly being stimulated into growth and flowering by the fire that often precedes the onset of rain. Annual species, in contrast, use the moist summer season for growth and come into flower towards the end of the summer, their flowers often persisting long into the winter dry season (see Chemás-Jaramillo and Bullock (2005) for examples from Mexico). Most dry forest and semi-desert species flower during the summer rainy season, taking advantage of the short wet period to produce their flowers. One subset, however, prefers to flower in the height of the dry season when they are leafless so their seeds are mature when the rains eventually begin (Ipomoea schulziana, I. juliagutierreziae). Plants of flooded pampas flower after the waters recede during the winter. There is no clear pattern amongst species of moist forest. The archetypical rain forest species, I. philomega flowers at the height of the summer but other moist forest species such as I. regnellii and I. cryptica prefer the winter.

There are many individual subtleties, which need careful observation and recording before any explanation can be provided. In Eastern Bolivia in areas of a similar altitude and climate, the first author has observed the following sequence, although these observations may be partially dependent on the date of the onset of rain. To see flowering specimens of I. hirsutissima, I. cerradoensis and I. psammophila, it is best to visit in October and November; to find I. schomburgkii, I. aprica, I. caloneura and I. paulistana it is best to look in December or January; to find I. graniticola and I. densibracteata February to early March would be best; March to early April would be good for I. amnicola, I. abutiloides and I. megapotamica; April to June would be good to find I. bonariensis, I. argentinica, I. rubens, I. bahiensis and I. cordatotriloba; to find I. ramosissima, I. setifera, I. paludicola or I. eriocalyx June or July would be best, while July or August might be best for I. regnellii, I. lactifera and I. cryptica. Finally you should note that you might find I. maurandioides in flower at almost any season.


Ipomoea species are commonly named “Morning Glory” because the flowers of several cultivated species, notably I. indica, open at dawn and close before midday. However, while this observation may be a useful generalization, it is only a partial truth. Much depends on the strength of the sun and many morning-flowering species will continue in flower well into the afternoon on a dull day. Conversely night-flowering species, such as I. alba, I. muricata and I. violacea may remain open during clouded, sunless days. These observations indicate that research suggesting different species flower for a specific number of hours (Chemás-Jaramillo and Bullock 2005) should be treated with caution. However, there is no doubt about the truth of their observation that the flowers of some species, especially robust perennials, such as I. ampullacea, I. bracteata and I. pedicellaris, remain open for much longer periods than those of more slender species.

Economic uses

Much the most important species of Ipomoea economically is I. batatas, the sweet potato, which is reported to be amongst the ten most important staple food crops worldwide (Woolf 1992, FAO 2017). Although clearly of American origin it is widely cultivated in almost all tropical and subtropical countries for its root tubers (storage roots). The largest contemporary producer is China but much of Chinese production is used as animal fodder (FAO 2017). It has a number of important advantages as a human food. It is second only to the potato in productivity per hectare. It is more drought resistant than many important staple crops such as maize. The common orange-fleshed varieties are an outstanding source of Vitamin A and have significant quantities of Beta-carotene, potassium and various other elements important for human nutrition (Kurabachew 2015). Indeed per gram it is richer in potassium than bananas (USDA 2017. The purple-fleshed varieties have enjoyed a recent vogue as brain food but it is unclear whether this is merely a fashion fad or based on sound evidence.

Other species of Ipomoea produce root tubers but there are only occasional reports of their use, usually as a famine food. Amongst species whose tubers are reported to be used for food are I. leptophylla, I. pubescens, I. pandurata (Haddock et al. 2015), I. plummerae (Gutiérrez-R 2016) and I. serrana (Vasconcelas et al. 2016).

The leaves of some species of Ipomoea are used as a vegetable. Much the most important is I. aquatica, the water spinach or kangkong, which is widely used as a stir-fry vegetable in South East Asia, although it has not achieved much popularity outside the region. The leaves of other species are occasionally used as vegetables, including I. batatas itself and apparently I. littoralis (Austin 1991b), although it is unclear whether they enjoy general use or are a resort at times of famine. It is possible that the leaves of other species could be used as a vegetable but the leaves of some species are potentially harmful (Meira et al. 2012). Ipomoea malvaeoides and I. carnea subsp. fistulosa, for example, are avoided even by goats and are unpalatable, if not actually poisonous, to animals and presumably to humans.

Various species of Ipomoea are cultivated as garden ornamentals. In extra-tropical countries, relatively quick growing annual species are favoured, particularly I. indica, I. purpurea, I. nil, I. quamoclit and I. tricolor. In tropical countries, perennials are more common. The most conspicuous is I. carnea subsp. fistulosa, which is widely cultivated for its erect habit and profuse flowers. Ipomoea cairica is often planted to cover walls and unattractive bushes. Ipomoea alba and I. muricata are also sometimes grown in gardens and on boundary fences. Ipomoea horsfalliae is a widely planted liana that is grown in many tropical countries for its attractive red flowers, but is not reported to set seed and so is never naturalized. Ipomoea quamoclit and, less commonly, I. lobata are also grown quite frequently and sometimes become naturalised. There are occasional reports of the cultivation of other species including I. nervosa, I. pauciflora and I. intrapilosa but this is not common practice.

Various species of Ipomoea have had medicinal uses since pre-Colombian times, broadly for two purposes. The seeds of several species are known for their hallucinogenic properties as they contain small quantities of LSD-like substances (Steiner and Leistner 2018). Amongst the species used as a hallucinogen are I. tricolor “Heavenly Blue”, I. purpurea, I. alba, I. corymbosa and I. nervosa. The roots of several species have been used as a purgative and marketed under the name “jalapa”. Ipomoea purga is the best-known species used for this purpose but others such as I. simulans, I. orizabensis and I. jalapa are sometimes reported as having similar properties, although their medical value requires confirmation. Meira et al. (2012) document many actual and potential medical uses of Ipomoea species.

Morphological characters and their use in species delimitation

In the following section we discuss the range of characters which have proved useful in species delimitation and have indicated some of the pitfalls in their use. Taxonomic decisions often have to be made using incomplete material. Many species of Ipomoea are extremely localized in their distribution and many of their morphological characters are unknown, particularly the roots and the fruit characters, which are unknown for perhaps a third of species.

Habit and lifeform

Species of Ipomoea may be annual or perennial, herbaceous or woody, twining (or at least scrambling), erect, decumbent or prostrate. All of these characters are potentially useful in species delimitation and are used in the keys. It is useful, for example, to distinguish between lianas and scandent herbs or between prostrate or erect herbs but the distinctions need to be treated with caution. Many species have a woody rootstock and herbaceous stems, which may or may not be woody at the base. Stems may become somewhat woody with age. Twining plants may be trailing in the absence of shrubs to climb on. We have also avoided the use of the term vine as it is sometimes used to mean a woody climber (like the grape vine), so almost a synonym of liana, and sometimes to mean a relatively slender twining plant.

Annual species are characterized by having fibrous roots and typically flower in the late rainy season (tropical summer) as they require sufficient time to reach maturity after the onset of rains. In the herbarium, in the absence of roots, annuals can often be identified by their slender habit and the presence of mature capsules on flowering specimens. Perennial species, in contrast, are relatively stout and often lack mature capsules on flowering specimens or are almost entirely without corollas on fruiting specimens. It is possible that some normally annual species perenniate under suitable circumstances, especially in areas with no distinct dry season. There are no known erect annual species. Annual species are not found in Clades A1 or A2. In contrast they are well-represented in the Batatas (A3 in part), Pharbitis (B1 in part), Quamoclit (B2 in part) and the Pedatisecta Clades (B2 in part).

The majority of species are twining perennial herbs or lianas with petiolate, ovate, cordate leaves. The inflorescence is formed of pedunculate axillary cymes, the cymose structure usually being very obvious, although the cymes are sometimes reduced to single flowers. There is a tendency for some of the lianas to develop inflorescences on short leafy branchlets, rather than from the axils of the stem leaves.

Somewhat similar is a less well-defined assembly of essentially trailing plants. At one extreme these species root at the nodes and form extensive mats, in one case (Ipomoea aquatica) extending its stems to float on shallow water. Two widespread submaritime species, I. pes-caprae and I. imperati, are good examples of this growth form. More common are trailing species that do not root at the nodes. They usually grow in open, often sandy inland habitats. These trailing species often have shortly petiolate, elliptic leaves rounded to truncate at the base combined with axillary cymose inflorescences, these sometimes being shortly pedunculate. These trailing plants are, thus, apparently intermediate morphologically between the true climbers and the erect species. Some trailing species are morphologically indistinguishable from the climbers, the prostrate habit apparently the consequence of the absence of suitable plants to climb. Ipomoea maurandioides, a South American species principally of rock outcrops, is one such example.

The erect habit is usually associated with subsessile, oblong, lanceolate, or oblong-elliptic cuneate-based leaves with a terminal inflorescence, the upper leaves clearly bract-like and the pedicels and peduncles reduced so the inflorescence is subracemose or even subspicate in form. Species with this habit occur mostly in open grasslands and especially in the cerrados of South America. Most species produce annual stems from a tough woody perennial subterranean xylopodium, which is resistant to fire, a characteristic and perhaps defining feature of these habitats. Erect species are found in many different clades but are unknown in the Batatas, Quamoclit and Pharbitis Clades and rare in Clade B.

The erect habit is also associated with a number of shrubs and small trees often treated as Section Arborescens. These usually (always?) have white latex and often flower when leafless or nearly leafless. The inflorescence often develops on short branchlets and is not obviously axillary and cymose in structure. The corolla is white with a dark centre, subcampanulate to funnel-form in shape and possibly bat-pollinated (Felger and Austin 2005). Species with these characteristics mostly occur in very dry forest along the mountain chains of Mexico, Central America and the Andes and are completely absent from Brazil and the Caribbean.

Much the most widespread and common erect species, Ipomoea carnea subsp. fistulosa fits none of the above characteristics, having ovate cordate leaves and pink flowers in axillary cymes but its uniqueness is perhaps a consequence of its close relationship with Ipomoea carnea subsp. carnea which is a characteristic climbing species, from which it is presumably diverged.

Underground parts

Although annual species are generally known to have fibrous roots, little reliable information is available about most of the perennial species. Erect species of the cerrado nearly always arise from a woody xylopodium but this is known to vary considerably in form and development from species to species. Ipomoea hirsutissima, for example, has very large somewhat woody tuberous roots. Similar storage roots are seen in other species in Clade A1 including I. lilloana (Figure 15D) and I. opulifolia (Figure 15E). The best-known species for its tuberous rootstock is, of course, the edible I. batatas, but storage roots occur in many different clades throughout the genus, such as I. bonariensis and I. platensis in Clade A2, this last sometimes cultivated as a succulent. Those of I. pubescens and I. plummerae in Clade B are sometimes eaten, while those of I. pandurata and I. leptophylla in Clade C are noted for their size. Other species have tubers which can be used medicinally, notably I. purga and I. jalapa. However, for the vast majority of species there is no accurate information about their rootstock. Although this character may prove to be of economic importance in the future and is significant in discussions around the origin of the sweet potato (Muñoz-Rodríguez et al. 2019), it can be little used at the present time in species delimitation.


White latex is recorded as present in many species and is sometimes abundant, notably in trees and lianas, including species in the Arborescens and Calonyction Clades as well as in the aptly named Ipomoea lactifera. However, its presence often goes unrecorded and it may be more or less obvious according to climatic conditions.


Stems may be entirely herbaceous, woody in the lower parts and herbaceous above, or entirely woody except for the new growth. Stems may be glabrous or variously hirsute, the indumentum usually being similar to that of the peduncles, petioles and leaves, especially the abaxial surface of the leaves. There is a tendency for older stems to be somewhat glabrescent. Unusual features of the stem include distinct wings (Ipomoea pterocaulis, I. splendor-sylvae, I. subalata, I. kahloae), squamose dark glands (I. balioclada), warty protuberances (I. verruculosa, I. tuboides), spinules (I. spinulifera), soft spines (I. setosa), soft fleshy teeth (I. muricata, I. alba, I. parasitica) and granulose protuberances (I. granulosa).


Species may be glabrous or variously hirsute. There is a good deal of intra-species variation and this has often proved to be an unsatisfactory character in species delimitation. Many species or varieties have been recognized over the years based on the presence or absence of hairs and have subsequently been abandoned. Despite this important proviso, many species have a characteristic indumentum which is readily recognized. Species which are always glabrous in their vegetative parts form a long list, as do those which are characteristically sericeous or tomentose. A sericeous indumentum is characteristic of almost all species previously placed in Argyreia, Rivea, Turbina and Stictocardia as well as many that have always been included in Ipomoea. Some unusual indumentum types include:

• Stellate hairs. These are characteristic of certain species notably Ipomoea bonariensis from South America, I. scopulorum from Mexico and I. luteoviridis from Hispaniola. In cases where they are mixed with simple hairs they may be very difficult to observe and pass unnoticed. They are also characteristic of the Astripomoea Clade, which is restricted to Africa.

• T-shaped hairs. Ipomoea malpighipila was named on the basis of the presence of T-shaped hairs. They are not reported from other species, except the related I. aemilii, and are difficult to observe even in these species.

• Scattered long fine hairs. Ipomoea clavata, I. dolichopoda.

• Density and appearance. Many species are densely hairy especially on young stems and the abaxial surface of leaves but sometimes on all vegetative parts. Where hairs are dense the leaves are often white or grey in colour and characteristic of the species. This kind of indumentum is not always easy to define and is sometimes described as canescent, sericeous, tomentellous, tomentose or densely pubescent by different authors.

• Gland dots. Distinct gland dots are found in some species, especially on the abaxial leaf surface but sometimes on other vegetative parts or even the corolla. They usually appear as dark dots and are so characteristic of I. tiliifolia that they are often regarded as a defining characterstic of the Stictocardia Clade (Austin and Demissew 1997). They occur sporadically elsewhere as in some specimens of I. megapotamica, I. reticulata and I. batatoides. As white dots they are characteristic of I. eremnobrocha and the related species I. isthmica and I. peteri.

Extrafloral nectaries

These have been reported in many species including Ipomoea alba, I. batatas, I. bonariensis, I. carnea, I. indica, I. leptophylla, I. mauritiana, I. muricata, I. pes-caprae and I. tuboides (Keeler 1977, 1980, 1985, Keeler and Kaul 1979, Mondal et al. 2013, Meeuse and Welman 2000). These are usually found on the petioles, at the base of the leaf where it joins the petiole or on the sepals. It is postulated that they attract ants which help to protect the plant from predators. However, they are not readily observed and their taxonomic value is uncertain as they are not necessarily constant in a particular species (for an example, see the discussion about I. indica in Keeler (1985). The case of I. tuboides is particularly interesting as there are no native ants in Hawaii, suggesting perhaps that the nectaries evolved in the ancestor of this species before it was dispersed to Hawaii from the American mainland.


Leaves are exstipulate but a few species have pseudo-stipules (notably Ipomoea cairica, I. fissifolia and I. quamoclit), formed by modified leaves or prophylls. Leaf size can be distinctive but difficult to quantify diagnostically. Large leaves are a feature of a few species such as Ipomoea ampullacea, I. magnifolia and I. philomega whereas small leaves are characteristic of many annual species but also of some perennials such as I. hartwegii and I. rupicola.

Leaf shape is mostly related to habit with almost all climbing species having ovate to deltoid leaves with a truncate, cordate or sagittate base. Elliptic leaves are rare and mostly found in trailing species. Lanceolate, oblong or oblong-elliptic leaves are mostly a feature of erect species. Some unusual shapes occur, such as the strap-shaped leaves of I. tenuissima.

Leaves may be entire or variously divided. Pinnate leaves are only present in Ipomoea quamoclit, and pinnatifid to lyrate-dentate leaves in a few Mexican species (I. ancisa, I. sescossiana, I. tacambarensis, I. stans). A much larger number of species have leaves palmately lobed. The number of lobes, usually 3 or 5, occasionally more, and the depth of lobing are often characteristic of a particular species. However, leaf lobing is often an inconstant character, many species having entire-leaved forms or forms that intergrade with the normally lobed forms. The leaves of some, such as I. bonariensis, I. clausa, I. microdactyla or I. mauritiana are notoriously variable in form. A relatively small number of species have leaves palmately divided into separate leaflets and this character is usually constant. Species which present forms with both lobed leaves and leaves divided into separate leaflets occur in only a very few species (I. cairica, I. bonariensis, I. homotrichoidea).

The leaf base is sometimes distinctive, particularly in those species that have leaves with strongly cordate or strongly cuneate bases. Sagittate or hastate leaves are also often distinct but may intergrade with the more common cordate leaf base. Rounded leaf bases often intergrade with shallowly cordate or truncate leaf bases and are difficult to characterize.

The leaf margins are usually entire to slightly undulate but a few species have distinctly dentate leaves (I. odontophylla, I. schaffneri, I. noctuliflora, I. ignava, I. peruviana, I. descolei and I. erosa). A few species may have 1–several rather large teeth on the margins, usually towards the base (I. acanthocarpa, I. dumetorum, I. eriocalyx). In the majority of species the leaf apex is acute to acuminate, although the actual tip may be somewhat obtuse. The tips are commonly mucronate but in a few cases the midrib extends as a mucro several millimetres in length (I. walteri). In a few species the apex is distinctly retuse (I. pes-caprae).

In general, petiole length is of little significance except that short or absent petioles correlate with an erect habit and elongate leaf shape as noted earlier. One curious feature is the fusion of the petiole and the peduncle at least for part of their length (I. connata, I. bracteata, I. dumosa).


Most inflorescences consist of cymes that arise from the leaf axils. Cymes are nearly always solitary but are very variable in the number of flowers. In many species the cymes are reduced to a single flower while in others the cymes may be compounded with up to 15 or more flowers. The number of flowers in the cyme is often a useful although somewhat imprecise taxonomic character.

Not all inflorescences are obviously cymose in structure, some are more or less corymbose (especially in the Quamoclit Clade) or racemose (e.g. Ipomoea bombycina, I. reticulata, I. corymbosa) or umbellate (some forms of I. batatas), even appearing paniculate in some forms of I. lineolata or I. philomega. In quite a few species, the pedicels are very short so the inflorescence is subcapitate in form. In the Arborescens Clade and also in a number of woody lianas, the inflorescence arises on short leafy (bracteate) branchlets with no obvious cymose structure.

Bracts and bracteoles

We have generally avoided using the term bract since in most twining or trailing species, the bracts are not clearly differentiated from the leaves, the cymes arising in the axils of the leaves which function as bracts. In the erect species and also in some or the arborescent species where the inflorescence is either terminal or borne on small branchlets bracts are more clearly differentiated from leaves, typically smaller and narrower and diminishing in size towards the branch tips and, in this situation, we have used the term bract. Some authors, however, use the term bract for the very different structures that arise at the inflorescence branching points or at the base of the pedicel in unbranched inflorescences. We refer to these as bracteoles, only rarely differentiating between primary bracteoles (at the first branching point) or secondary bracteoles (at the higher branching points) as these rarely differ in any significant way. In many species the bracteoles are inconspicuous and caducous (and have never been observed in a few species), but in others they are prominent and persistent, especially in the Pharbitis Clade, and occasionally even forming an involucre around the flowers where the pedicels are very short, notably in I. neurocephala and I. involucrata.

In the majority of species the bracteoles are small (< 3 mm long), often linear, lanceolate or scale-like and caducous. In a few species, Ipomoea blanchetii is an example, we have not observed bracteoles in any specimen available to us. In others, they are relatively persistent, particularly in species, with a subcapitate inflorescence. These include I. indica, I. villifera, I. mairetii, I. argentinica, I. asplundii, I. chrysocalyx, I. racemosa, I. amazonica, I. eriocalyx, I. setifera, I. fimbriosepala, I. burchellii, I. pohlii and I. mcvaughii. In a very few species the bracteoles are expanded, persistent and form an involucre around the inflorescence as in I. neurocephala, I. involucrata, I. bracteata and I. suffulta.

Peduncles and pedicels

Peduncles may be short or long and the length is sometimes significant. Most species with a terminal inflorescence have very short peduncles and pedicels. However, some trailing or twining species are also remarkable for their relatively short peduncles. These include Ipomoea eriocalyx and a miscellaneous group of other species, such as I. lindenii, I. chapadensis, I. riparum and I. chrysocalyx but is most common in Clade A2. Species in this clade with very short peduncles include I. microdonta, I. lachnea and I. calophylla from the Caribbean, I. goyazensis from South America, I. isthmica and I. heterodoxa from Central America and I. pseudoracemosa, I. pruinosa, I. conzattii and I. tehuantepecensis from Mexico. Many of these species with short peduncles also have short pedicels so the whole axillary inflorescence is very compact. However, there is also a group of species with relatively long peduncles but a subcapitate inflorescence in which the flowers are borne on short pedicels. This is particularly characteristic of the Pharbitis Clade (I. indica, I. neurocephala, I. mairetii, I. lambii and I. villifera) but is also noteworthy amongst many unrelated species including I. racemosa, I. amazonica, I. argentinica, I. bahiensis, I. eriocalyx, I. fasciculata, I. exserta and I. batatas. Species with pedunculate subcapitate inflorescences often but not always have a bracteolate inflorescence. Very long peduncles are also distinctive in species such as I. marcellia, I. macdonaldii, I. longibarbis, and I. austrobrasiliensis. Unusually long pedicels are rarely apparent but are a feature of I. pedicellaris and its allies which include I. regnellii, I. lindenii and I. tentaculifera, these inflorescences appearing very lax. Unusual features of the peduncle include the winged peduncles of I. decemcornuta and I. kahloae, the peduncle fused with the petiole for some of its length (I. connata, I. dumosa, I. bracteata) and the peduncle that passes through the leaf sinus (I. aristolochiifolia, I. huayllae). Very occasionally pedicels are unusually slender and coiled (I. heptaphylla, I. tenera).

Sepals (Figures 27)

The calyx is formed of five overlapping, free sepals. The two outer sepals are usually similar in size and form as are the two inner sepals, which often have relatively broad, scarious, glabrous margins. The middle sepal is intermediate in size and shape and is commonly asymmetrically scarious. The sepals are often of considerable taxonomic significance and constitute important conserved characters at the species level. The differences in size and shape between the inner and outer sepals are often of great significance. The apex is frequently especially diagnostic. Many species have mucronate sepals, but the mucros are often caducous so some or even all sepals may appear muticous or retuse. Also important is the abaxial surface of the outer sepals which may show all kinds of variation in indumentum, venation and surface which can be smooth, muricate or armed with soft spines. In a few species notably in the Arborescens Clade, the presence of hairs on the adaxial surface is significant. As observed by Hallier (1893a), the sepals are accrescent in fruit, more especially so in the lianas such as I. brasiliana or I. tiliifolia, sometimes doubling their size after anthesis and becoming wider so sepals which were lanceolate at anthesis may become ovate in fruit. They may also enclose or nearly enclose the capsule.

Many sepals display unusual features including:

• Very unequal sepals: I. anisomeres, I. cryptica, I. squamosa, I. asarifolia, I. paludicola, I. maurandioides, I. macedoi.

• Adaxial (inner) surface hirsute: Arborescens Clade, I. longibracteolata, I. magna.

• Subterminal awns: all species in the Quamoclit Clade.

• Sepals terminating in a long awn: I. alba, I. muricata, I. nil, I. hederacea. Sepals of some other species, such as I. incarnata, may be interpreted as terminating in an awn.

• Sepals with fleshy spine-like trichomes: I. crinicalyx, I. echinocalyx, I. altoamazonica, I. silvicola, I. setosa, I. tentaculifera, I. lozanii (smaller than in other species),

• Sepals with a prominent abaxial appendage, I. rosea, I. bahiensis; I. decemcornuta.

• Sepals with swollen abaxial tumour: I. appendiculata.

• Sepals with 1–2 prominent black abaxial glands: I. hieronymi, I. megapotamica.

• Sepals muricate: I. plummeae, I. capillacea, I. madrensis, I. aristolochiifolia, I. pedicellaris, I. obscura, I. ochracea, I. cairica, I. asarifolia, I. paludicola, I. procurrens, I. coriacea.

• Sepals with prominent longitudinal ribs: I. fimbriosepala, I. setifera, I. parvibracteolata, I panduata.

• Sepals with fimbriate margins: I. tenera, I. sidifolia (sometimes).

• Sepals with a prominent cordate base: I. macedoi, I. apodiensis, I. pantanalensis, I. pubescens, I. lindheimeri.

The great diversity of sepal form is curious and not easily explained. It has been suggested that the development of coriaceous and large sepals may have evolved in response to the need to protect nectar glands from robber insects. (McDonald 1991).

Figure 2. 

Sepals of Ipomoea species. A I. setifera B I. dumetorum C I. aristolochiifolia D I. crinicalyx E I. plummerae F I. bahiensis G I. amnicola H I. appendiculata. Photographs of A (Wood et al. 27771) B (Wood et al. 27654) D (Wood et al. 27606) and G (Wood et al. 27706) by Beth Williams C (Wood 27926) H (Wood et al. 28024) by John Wood E by Mario Giorgetta F (Queiroz et al. 15950) by Hibert Huaylla.

Figure 3. 

Sepals of Ipomoea species. A I. pauciflora B I. bernoulliana C I. tentaculifera D I. hartwegii E I. murucoides F I. pantanalensis G I. hederacea H I. funis. Photographs of A (Harling et al. 15403) B (Standley 27496) C (Pringle 6702) D (Santos Martínez 2228 E (Pringle 6066) F (Pott 6399) G (McCarthy s.n.) H Andrieux 600 by John Baker.

Figure 4. 

Sepals of Ipomoea species. A I. racemosa B I. rosea C I. alba D I. hirsutissima E I. barbatisepala F I. ampullacea G I. gigantea H I. longeramosa. Photographs of A (R.A. & E.S. Howard 8863) E (González Ortega 874) and F (Lott & Wendt 2192) by John Wood; B (Harley et al. 54830); C (Fendler 589) and H (Pickersgill et al. RU72-400) by John Baker; D (Mendoza 4365) and G (Mendoza 4645) by Moises Mendoza.

Figure 5. 

Sepals of Ipomoea species. A Ipomoea descolei B I. paraguariensis C I. australis D I. purpurea (left), I. nil (right) E I. incarnata F I. pintoi G I. maurandioides H I. pubescens. Photographs of A by Hector Keller; B and G by T. Carruthers; C (Wood et al. 27708); E (Wood 27756) and H (Wood 27675) by Beth Williams; D by John Pink; F (Queiroz 15956) by Hibert Huaylla.

Figure 6. 

Sepals of Ipomoea species. A I. argyreia B I. tricolor C I. argentea D I. syringiifolia E I. eriocalyx F I. procurrens G I. tarijensis H I. regnellii. Photographs of A (Mendoza 4899); C (Mendoza 4705) and F (Mendoza 4900) by Moises Mendoza; B (Wood & Soto 27960) and H (Wood & Soto 27951) by Daniel Soto; D by Hector Keller; E (Wood et al. 27809) by Beth Williams; G (Wood 27920) by John Wood.

Figure 7. 

Sepals of Ipomoea species. A I. meyeri B I. ternifolia C I. cryptica D I. heterodoxa E I. sericosepala F I. splendor-sylvae G I. squamisepala H I. trifida. Photographs of A (Anderson 1895) B (Pringle 4439) C (Soto et al. 1331) E (Wood & Soto 27550) F (Wilkin 472) and H (Smith 1570) by John Baker; D (Wallnöfer 9506) by John Wood; G (Mendoza 4902) by Moises Mendoza.

Corolla (Figure 8)

The corolla is most commonly funnel-shaped, but is quite often campanulate, or hypocrateriform, or sometimes suburceolate, the limb usually prominent, entire or shallowly lobed but occasionally deeply lobed, or much reduced and present only as five indistinct teeth. The corolla exterior has five prominent midpetaline bands, which may be more darkly coloured and/or more pubescent than other parts of the corolla exterior. The corolla is very variable in size from less than 1 cm long in species like I. eriocarpa or I. minutiflora to over 10 cm in length in species like I. jalapa, I. megalantha, I. parvibracteolata, I. subalata and I. pterocaulis. Size is an unsatisfactory character at one level because of its variability within individual species, but is nonetheless often characteristic of a particular species.

Figure 8. 

Corollas showing variations in form (side view), size, limb lobing and stamen exsertion. A Ipomoea argentea B I. repanda C I. neei D I. electrina E I. habeliana F I. santillanii G I. nationis H I. rubriflora J I. longistaminea K I. megapotamica L I. megalantha M I. neriifolia N I. syringifolia P I. ramosissima Q I. elongata R I. mucronatoproducta. A from Wood et al. 25639 and photo; B from Whitefoord 5244; C from Skutch 2043; D from Breedlove 27626; E from Bentley 203; F from Bourgeau 3024; G from Saunders 987; H from Wood et al. 27678; J from Pastore et al. 2678; K from Wood et al. 28060; L from Hassler 9114; M from Rezende et al. 1011; N from Stutz 1426 and photo; P from Bang 2246; Q from Purpus 3904; R from Wood & Villarroel 25474. Drawn by Rosemary Wise.

Corolla shape is usually, perhaps always, related to pollination. The commonest corolla shape consists of a very short subcylindrical basal tube which is then gradually widened to the mouth. Corollas of this type are described as funnel-shaped, are usually, pink, sometimes blue or white, in colour and are apparently pollinated by bees. The limb is entire, undulate or shallowly (very rarely deeply) lobed. When the corolla is very short, the tube is more abruptly widened from the base and is campanulate in form. This is characteristic of some species in the Batatas Clade and also of small-flowered species with a cream corolla, such as Ipomoea reticulata, I. corymbosa and I. syringiifolia. This kind of corolla tends to intergrade with the common funnel-shaped corolla. The corolla of the Arborescens Clade and some other, mostly woody liana species is shortly funnel-shaped (almost campanulate), white or white with a dark purple centre. These flowers may be bat-pollinated (McDonald 1991: 73, Felger and Austin 2005, Queiroz et al. 2015) but confirmation is needed in most cases.

Other corolla shapes are less common. A hypocrateriform or salver-shaped corolla in which the nearly cylindrical corolla tube is only slightly widened at the mouth is associated with red flowers, exserted stamens and bird pollination. This corolla type is characteristic of the Quamoclit Clade but is also fairly common in the Clade A2 in South America (Ipomoea exserta, I. longistaminea, I. ana-mariae, I. verruculosa), and especially the Caribbean (I. argentifolia, I. digitata, I. microdactyla, I. steudelii). In Mexico and northern South America it is more commonly associated with Clade B in the Pharbitis Clade (I. jamaicensis) and elsewhere (I. bracteata, I. dumosa, I. chenopodiifolia, I. retropilosa, I. tubulata). Occasionally the corolla limb is very deeply lobed as in I. repanda, I. hastigera, I. electrina (which is orange, rather than red). An occasional variation is the suburceolate corolla, in which the corolla tube is essentially cylindrical but somewhat swollen in the middle and with a short corolla limb consisting of small teeth. Ipomoea suburceolata from Bolivia, I. lobata and I. tehuantepecensis from Mexico and I. praecox from Cuba have flowers of this kind. nother variation is found in plants with a white or pale blue corolla in which the tube is exceptionally long. This type of corolla is associated with night-flowering hawk moth pollinated species. The best-known species of this type is I. alba but there are various others with similar corollas including I. habeliana, I. violacea, I. tuboides, I. scopulorum, I. riparum, I. santillanii, I. chiriquensis, I. ampullacea, I. macdonaldii and I. lottiae. Species with this kind of corolla are notably more common on oceanic islands and in Mesoamerica and Mexico than elsewhere.

Corolla colour. Field and herbarium observations of flower colour need to be treated with caution. Flowers change colour during the course of the day, most obviously in the case of Ipomoea nil, which is blue when fresh but turns pink as it ages and appears pink in herbarium specimens. Equally, one collector’s purple is another collector’s pink or lilac or even red. Although the great majority of species have a corolla colour that is generally described as pink, there are many exceptions. White flowers (often with a dark centre) are characteristic of the Arborescens Clade and of several other woody liana species, such as I. magna, I. longibracteolata, I. brasiliana and I. paradae, and are in some cases pollinated by bats. Night-flowering moth pollinated species typically with a hypocrateriform corolla, such as I. alba, I. santillanii, I. habeliana, I. violacea, I. ampullacea have pure white corollas. Campanulate or funnel-shaped white flowers are noted for many different species in different clades but are more common in the Batatas Clade (I. lactifera, I. lacunosa), Clade A1 (I. cerradoensis, I. macrorhiza, I. langsdorfii, I. vivianae, for example) and Clade A2 (I. proxima, I. suaveolens, I. pruinosa) but occasionally occur elsewhere (I. imperati). Many usually pink-flowered species are recorded as sometimes being white-flowered (I. acanthocarpa, I. bahiensis, I. carnea). Slightly different are those species with creamy or violet-tinged flowers such as I. lindenii, I. corymbosa, I. saopaulista, I. minutiflora and I. syringiifolia. Truly yellow flowers are rare in American Ipomoea but include I. ochracea, I. longeramosa and I. lutea. There are many subtle variations between red and pink. Red flowers being principally a feature of the Quamoclit Clade, some Caribbean species (I. montecristina, I. microdactyla, I. repanda and a few South American species notably I. cavalcantei). Some corollas are described as purple and include forms of I. indica, I. cuzcoensis and I. magnifolia. Blue flowers also occur and are often associated with a white corolla tube. I. hederacea, I. nil, I. aristolochiifolia, I. tricolor, I. marginisepala and I. cardiophylla are species with this corolla colour.

Corolla indumentum. The indumentum of the corolla exterior is best observed on buds as there is some evidence that hairs are caducous in some species as the corolla matures. Hairs are often difficult to see on open corollas but are best searched for at the tips of the midpetaline bands. Although previous studies have not seen corolla indumentum as particularly important taxonomically, we have found it of great significance both at species and clade level. It is nearly always constant in a particular species, exceptions being very rare and their existence raising doubts about the circumscription of the species in the few cases where it has been noted (Ipomoea lindenii, I. wolcottiana, I. brasiliana). All species of the Quamoclit and Batatas Clades have corollas glabrous on the exterior. All species in Clade A2 have coriaceous sepals and glabrous corollas (except I. discolor). All species in the very large Jalapa radiation (Species 1–83) have pubescent corollas.


The stamens are of little taxonomic value. They are always five and may be included or exserted. If they are included they are unequal with two noticeably longer than the other three but, if exserted or near exserted, they are subequal in length. The filaments are slightly expanded near the base but are occasionally thickened and subtriangular as in Lepistemon and some forms of Ipomoea batatoides. The filaments are always glandular pilose at the base. In a few species hairs are reported to extend upwards along the filament and this has been used as a diagnostic character in the Batatas Clade. (Austin 1978b).

Pollen (Figures 9, 10)

The pollen of Ipomoea is always globose and pantoporate with large supratectal elements that form acute or blunt spines. The presence of these echinulate supratectal elements is the diagnostic synapomorphy for Ipomoea within Convolvulaceae. Within this general pollen-type subtle variations are visible in the size of the pollen grains, in the number and shape of pores, in the number and structure of the supratectal elements, in the structure of the area surrounding the pores, the presence or absence of ‘basal cushions’ sensu Wilkin (1993) at the base of the supratectal elements and the extent of columellae in different parts of the pollen (Sengupta 1972, Pedraza 1983, Wilkin, 1993). In addition, individual pollen grains may look very different depending on whether the opercula or aperture membranes remain intact (Figure 10A, C–H) or not (Figure 10B) after acetolysis.

Figure 9. 

Pollen of Ipomoea species. A I. hieronymi (Wood et al. 28055) B I. wolcottiana (Hughes et al. 1911) C I. bonariensis (Wood et al. 27871) D I. bahiensis (Queiroz 15975) E I. maurandioides (Krapovickas & Cristóbal 1573) F I. corymbosa (Jurgensen 612) G I. sericosepala (Wood 28122) H I. tiliifolia (Beddome 5581). Photos by Robert Scotland.

Figure 10. 

Pollen of Ipomoea species. A I. triloba (D’Arcy 317) B I. cryptica (Steinbach 6311) C I. purpurea (Parada & Rojas 2664) D I. alba (Wood et al. 27828) E I. dumosa (Hinton et al. 9479) F I. hederifolia (Queiroz 15975) G I. stans (Y. Mexia 275112) H I. suffulta (Pringle 4755). Photos by Robert Scotland.

Our own survey of Ipomoea pollen confirms these previous studies demonstrating continuous variation in pollen morphology with little, if any, discrete variation that correlates with phylogeny. The attempt by Wilkin (1993) to correlate results with a broader infrageneric classification of Ipomoea was made in the pre-molecular era and does not correspond closely with our molecular results. Nevertheless, although pollen in itself is of little phylogenetic or taxonomic value within Ipomoea, a few broad generalisations can be cautiously made. The pollen of species in Clade A (Figure 9, A–C) usually has fewer supratectal elements (spines) than the pollen of species in other clades. Pollen in Clades B and C (Figures 9D, E, 10C–H) often shows a regular pattern of 4–6 supratectal elements per pore as exemplified by Figure 10C and 10G but this is not always the case (Figure 10A, H). The pollen of I. alba (Figure 10D) and related species in the Calonyction Clade (species 271–274) have characteristic stout, rounded gemmiform spines rather than the usual acute spines, but similar blunt spines are also found in other more distantly related species such as I. dumosa (Figure 10E).

In summary, the pollen of Ipomoea is characterised by echinulate supratectal elements, showing a number of features that vary continuously and some specific morphologies that are homoplastic.


The style is elongate, equalling or extended slightly beyond the anthers and nearly always glabrous, even in species with a hirsute ovary. The only exception we are aware of is Ipomoea sidifolia, in which the hairs extend for a short distance upwards from the ovary. The style is usually included in the corolla but is exserted in species with a hypocrateriform corolla. The stigmas are characteristically biglobose, that is they are bilobed with each lobe globose and appearing fused. They sometimes appear simply globose. Triglobose stigmas are characteristic of the Pharbitis Clade but are not reported from all species in the clade. Somewhat elongate stigmas are reported from African species placed in Astripomoea Clade but also occur in three species of the Arborescens Clade: I. pauciflora, I. populina and I. wolcottiana.

The ovary is narrowly ovoid in shape and usually glabrous. A pubescent or comose ovary is rare and only commonly found in the Batatas Clade. Most species have a bilocular ovary with two ovules in each chamber. This correlates with a biglobose stigma. A few species (Pharbitis Clade) have a trilocular ovary each chamber with two ovules, this correlating with a trilobed stigma. In species of the Quamoclit Clade, in Rivea, Stictocardia and most species placed in Argyreia, the ovary is 4-locular but with a single ovule in each chamber. Very rarely other arrangements are noted. In Ipomoea decasperma (and I. longituba Hallier f. from Madagascar) the ovary is 5-locular with two ovules per chamber but it is not clear whether this is constant in all examples of these species. Ipomoea gilana is reported to have a trilocular ovary.


The fruit may be an indehiscent, woody or somewhat fleshy structure or formed by a dehiscent capsule. In species with an indehiscent fruit, this is usually globose to ellipsoid in shape and may contain up to four seeds except in those species placed in Turbina where 1–2 seeds only are present. Indehiscent fruits are glabrous but some species placed in Argyreia have mealy fruits. In those species with a capsular fruit, the capsules may be globose, ovoid or conical in shape. Capsules are usually muticous but species with a prominent rostrate apex formed by the persistent style base are common. Most capsules are completely glabrous but in a few species, they are pubescent, pilose or comose, this correlating with a hirsute ovary (Ipomoea velutinifolia, I. dubia, I. sidifolia, I. dasycarpa, many annual species of the Batatas Clade). In the majority of species the capsule is bilocular with up to four seeds, though often less as a result of abortion. There are several exceptions. In the Pharbitis Clade capsules are usually trilocular and 6-seeded. Very rarely capsules have up to 10 seeds (I. decasperma). In the Quamoclit Clade the capsules are 4-locular but with only four seeds.

Seeds (Figure 11) are typically broadly oblong in outline and vary in size from species to species. Their colour (when ripe) can vary from black to varying shapes of brown, sometimes being distinctly reddish-brown. They can be completely glabrous, minutely covered in very short hairs (tomentellous), only visible under a microscope, pubescent, tomentose or, in many species, with prominent, usually white hairs which develop on the angles of the seeds, In a few cases the seeds are completely covered in matted woolly hairs (Ipomoea bombycina, I. eremnobrocha, I. isthmica, I. macrorhiza, I. jalapa). Although important in diagnosing species and species groups, the value of seeds as a taxonomic character is somewhat diminished by a number of factors. The seeds of many species are unknown; in some the marginal hairs are caducous so may appear absent (I. psammophila) and in others there may be more variability than can be demonstrated from the few fruiting specimens known (I. jalapa).

Figure 11. 

Seeds of Ipomoea A I. peteri B I. murucoides C I. carolina D I. eggersiana E I. longibarbis (with and without marginal hairs) F I. clavata G I. violacea H I. acanthocarpa J I. parvibracteolata K I. meyeri L I. jujuyensis M I. cholulensis N I. minutiflora P I. tiliacea. A from Wallnöfer & Tut-Tesucun 9662; B from Pringle 6066; C from Gillis 12906; D from Urote 35; E from Killeen et al. 4199; F from Fuentes & Miranda 10895; G from Stearn 322; H from Wurdack & Monachino 39830; J from Silva et al. 18; K from Smith 1573; L from Rose et al. 23251; M from Hinton 11166; N from Stevens & Montiel 26592; P from Curtiss 249. Drawn by Rosemary Wise.

Dichotomous keys

Keys are provided in a somewhat unconventional way and it is recommended that users follow the suggested steps in the order provided. Species in Steps 1–3 below also appear in the appropriate geographical keys. Note that species may enter several times in different places in the keys.

Step I. Does the plant fit any of the following distinct groups?

1. Plants of seashore (rarely inland in saline habitats): Ipomoea pes-caprae (pink flowers, retuse leaves), I. violacea (white to pale violet flowers, exserted stamens), I. imperati (white flowers, creeping herb), I. littoralis (Hawaii), I. sagittata (Caribbean and North American–sagittate lvs), I. macrorhiza (United States–white flowers, pubescent sepals).

2. Plants with a hirsute ovary and capsule: Ipomoea sidifolia, I. dasycarpa, I. velutinifolia, species in the Batatas Clade (page 387).

Step II. Is the plant one of the following very distinctive widespread common species?

An erect plant with ovate cordate leaves and pink flowers: 84b. I. carnea subsp. fistulosa.

A slender plant with pinnate leaves, pseudo-stipules and dark red corollas: 312. I. quamoclit.

A twining vine with pure white flowers, a narrowly cylindrical corolla tube and strongly awned sepals: 272. I. alba.

Step III. Does the plant belong to one of the following distinctive clades?

The Arborescens Clade (page 263). Trees, shrubs or lianas with white latex. Leaves entire. Sepals ovate or oblong, somewhat coriaceous. Corolla white, often with dark centre, glabrous or pubescent anthers included; seeds with long white marginal hairs.

The Batatas Clade (page 387) Annual or perennial herbs. Leaves entire or lobed. Sepals thin, often papery, usually distinctly mucronate. Corolla always glabrous, white or pink, often with a dark throat, often small and campanulate. Ovary and capsule often hirsute.

The Pharbitis Clade (page 430) Annual or perennial herbs, often hirsute. Leaves lobed or entire. Bracteoles often persistent. Sepals usually relatively large, usually with elongate, somewhat accrescent apex, sometimes leafy in texture. Corolla usually showy, pink, blue or violet, glabrous or (less commonly) pubescent. Stigma usually 3-lobed and ovary 3-locular. Capsule up to 6-seeded.

The Quamoclit Clade (page 556) Slender, twining usually annual, herbaceous herbs. Sepals characteristically awned, the awn subterminal on the abaxial surface, often equalling the sepal proper. Corolla red, orange or yellow, suburceolate or hypocrateriform, glabrous, stamens exserted or at least held at mouth of corolla. Ovary and capsule 4-locular.

Step IV. If your plant cannot be placed using Steps 1–3, go to the appropriate geographical key:

A. South American continent including the Galapagos Islands (page 54)

B. The North American Continent from Panama northwards (page 78)

C. The Caribbean Islands including Bermuda, Trinidad and the Netherlands Antilles (page 93)

D. Hawaii (page 99)

The two continental keys are divided into a series of subkeys to facilitate access as they would otherwise be very large. Some species can be accessed through different routes so individual species may occur in several subkeys.

A. Keys to South American species

Key A1: Species with soft fleshy spines on the sepals and/or peduncles

Key A2: Species with erect stems

Key A3: Species with leaves divided digitately to, or near the base, into five or more lobes or segments

Key A4: Species with very long sepals, mostly exceeding 2 cm in length

Key A5: Species with coriaceous, convex, usually glabrous sepals

Key A6: Species with a subcylindrical corolla tube and (usually) exserted stamens

Key A7: Species with small flowers, the corolla < 3 cm long

Key A8: Plants with a glabrous white corolla > 3 cm long (check buds).

Key A9: Plants with subcapitate inflorescences

Key A10: Trailing, climbing or twining plants with a pubescent corolla > 3.5 cm long

Key A1

Species with soft fleshy spines on the sepals and/or peduncles (Figure 15B). Excluded are species where soft spines are only on the stem, such as Ipomoea muricata and I. parasitica as these teeth occur occasionally in other species such as I. alba.

1 Leaves 3 (–5)-lobed 2
Leaves entire 3
2 Outer sepals 14–17 mm long, covered in long white hairs and soft spines; corolla white 411. I. altoamazonica
Outer sepals 8–10 mm long, glabrous or with soft spines; corolla pink 216. I. setosa
3 Outer sepals 15–25 cm long; peduncles < 5 cm long; corolla white 409. I. echinocalyx
Outer sepals 12–14 cm long; peduncles 0.5–8 cm long; corolla pink 408. I. crinicalyx

Key A2

Erect species. Perennial herbs or subshrubs growing in open habitats. Leaves subsessile (petioles usually < 1 cm), linear, lanceolate, ovate or oblong in shape, base attenuate or cuneate, rarely rounded, never cordate. Sepals various. Inflorescence usually terminal on the stem, often subspicate or subracemose in form but occasionally branched and arising from the upper leaf axils. Corolla shape and colour varied but never hypocrateriform (except I. cavalcantei) or suburceolate. Capsule and seeds varied.

1 Corolla glabrous on the exterior 2
Corolla hirsute on the exterior at least in bud 18
2 Leaves divided nearly to the base into linear segments; sepals > 2 cm long 13. I. theodori
Leaves entire or shallowly lobed 3
3 Sepals subequal, coriaceous, convex 4
Sepals equal or unequal, never coriaceous or convex 7
4 Leaves and stem glabrous 5
Leaves and stem hirsute 6
5 Herb; leaves linear, 1–3 mm wide 169. I. schomburgkii
Subshrub; leaves oblong or oblanceolate, 5–25 mm wide 155. I. franciscana
6 Leaves green, pubescent, imbricate, diminishing in size upwards; corolla weakly lobed 168. I. paulistana
Leaves silvery-sericeous, especially below, not conspicuously imbricate or diminishing in size upwards; corolla lobed 167. I. argentea
7 Sepals pubescent 8
Sepals glabrous 11
8 Corolla hypocrateriform, deep red; stamens exserted 96. I. cavalcantei
Corolla funnel-shaped, pink; stamens included 9
9 Outer sepals 6–10 mm long; leaves pubescent beneath 10
Outer sepals 12–15 mm; leaves glabrescent beneath 97. I. marabaensis
10 Leaves linear, 3–5 mm wide 102. I. neriifolia
Leaves mostly oblong, 5–14 mm wide 101. I. queirozii
11 Leaves pubescent beneath 101. I. queirozii
Leaves glabrous 12
12 Stems conspicuously granulose 368. I. granulosa
Stems smooth 13
13 Sepals subequal (Guianas and Amapá) 385. I. leprieurii
Sepals markedly unequal 14
14 Sepals abaxially muricate 15
Sepals abaxially smooth 16
15 Leaves oblong or ovate; plant only woody basally 345. I. procurrens
Leaves oblong-elliptic to suborbicular; woody subshrub 344. I. coriacea
16 Outer sepals 7–11 mm long 367. I. rupestris
Outer sepals 2–6 mm long 17
17 Leaves linear, < 3 mm wide 364. I. pinifolia
Leaves oblong, > 5 mm wide 363. I. squamisepala
18 Leaves all entire 19
Leaves 3–5-lobed 43
19 Leaves linear to very narrowly oblong; inflorescence clearly terminal (I. campestris might key out here but inflorescence is axillary) 20
Leaves oblong or ovate, > 5 mm wide; inflorescence clearly terminal only or with flowers also in the leaf axils 23
20 Leaves 16–27 cm long, coarsely tomentose 6. I. aemilii
Leaves 1.5–12 cm long, variously hirsute but not coarsely tomentose 21
21 Leaves acute, mucronate (widespread, cerrados) 47. I. aprica
Leaves obtuse, prominently mucronate 22
22 Leaves with 3 prominent longitudinal veins, abaxially floccose (Paraguay) 49. I. oblongifolia
Leaves with a single longitudinal vein, abaxially puberulent to subsericeous (Brazil) 48. I. uninervis
23 Inflorescence of unbranched terminal spikes or poorly differentiated cymose clusters 24
Inflorescence clearly branched, the lower part clearly cymose in structure, sometimes appearing paniculate 38
24 Leaves elliptic or ovate, up to three times as long as broad 25
Leaves oblong, lanceolate or oblanceolate, at least three times as long as broad 30
25 Pedicels absent or very short so bracteoles immediately below calyx; peduncles 2.5–5 cm long 50. I. guaranitica
Pedicels 2–7 mm long, bracteoles arising at least 5 mm below calyx; peduncles 26
26 Sepals 6–8 (–10) mm long; flowers in cymes, rarely solitary 27
Sepals 9–15 mm long; flowers usually solitary 29
27 Abaxial leaf surface and outer sepals densely silvery-tomentose; corolla pink (Paraguay) 55. I. paraguariensis
Abaxial leaf surface and outer sepals pubescent but not densely silvery-tomentose; corolla white or pink 28
28 Corolla white or pale pink; leaves 6 × 3.5 cm; plant ±herbaceous 33. I. cerradoensis
Corolla pink; leaves up to 15.5 × 7 cm; plant distinctly shrubby 34. I. sp . B
29 Peduncles very short; leaves with white “highlighted” ciliolate margins (Amambay, Paraguay) 54. I. estrellensis
Peduncles 0.8–4 cm; leaves without distinct white margins (Cordillera, Paraguay) 8. I. cordillerae
30 Plant inconspicuously hirsute, often appearing glabrous except when using a hand lens 31
Plant conspicuously hirsute 32
31 Plant usually > 50 cm in height; flowers in compact cymes, rarely solitary; wet places in Argentina, Paraguay and the Pantanal 9. I. paludosa
Plant usually < 30 cm high; flowers mostly solitary; dry places in the Brazilian cerrados 35. I. campestris
32 Bracts ±equalling leaves, nearly concealing flowers; leaves and bracts imbricate 103. I. pohlii
Flowers not concealed by bracts; leaves and bracts not imbricate, or, if somewhat imbricate, flowers and calyx clearly visible 33
33 Inflorescence elongate, up to 30 cm in length; leaves tomentose on both surfaces (Amambay, Paraguay) 53. I. rojasii
Inflorescence nor elongate, usually < 10 cm long; leaves not tomentose on both surfaces 34
34 Outer sepals mostly 15–20 × 5–7 mm, often somewhat foliose, much larger than inner sepals 83. I. burchellii
Outer sepals < 16 × 4 mm, usually much less, not conspicuously unequal 35
35 Sepals acute to acuminate 36
Sepals obtuse 37
36 Inflorescence very compact, clustered at apex of stem; sepals 8–11 mm long (Sierra de Pireneus in Brazil) 31. I. pyrenea
Flowers not clustered at stem apex; sepals 12–16 mm long (widespread in cerrado) 29. I. hirsutissima
37 Leaves lanceolate 30. I. aurifolia
Leaves oblong 32. I. subspicata
38 Leaves abaxially white, appressed tomentellous 38. I. argyreia
Leaves greyish, usually tomentose with spreading hairs 39
39 Leaves oblanceolate to obovate, widest above the middle 40
Leaves ovate, oblong elliptic or oblong, widest in the middle 41
40 Leaves mostly < 2 cm wide, densely pubescent adaxially; inflorescence simple, side branches absent or very short 39. I. cuneifolia
Leaves mostly 2–4 cm wide, thinly pilose to glabrous, adaxially; inflorescence with long side branches below 40. I. haenkeana
41 Leaves slightly longer than broad, adaxially much less hirsute than abaxially 41. I. virgata
Leaves 3 or more times longer than broad, both surfaces equally hirsute 42
42 Sepals acute, 10–12 mm long; ovary and capsule glabrous 42. I. verbasciformis
Sepals acuminate, submucronate, ±15 mm long; ovary and capsule comose 43. I. dasycarpa
43 Leaves divided to near the base into linear segments, all or most less than 3 mm wide 44
Leaves shallowly lobed or, if lobed to near the base, segments oblong, not linear 46
44 All leaf segments < 5 cm long 45
Some or all leaf segments 5–7 cm long 15. I. itapuaensis
45 Sepals 5–8 mm, obtuse to rounded; inflorescence usually terminal and cymose in form 17. I. angustissima
Sepals 9–11 mm, acute; inflorescence axillary; flowers solitary in the leaf axils 16. I. fiebrigii
46 Leaves shallowly lobed, often with some entire leaves 47
Leaves deeply lobed into oblong segments 49
47 Plant roughly hirsute with long spreading hairs; flowers solitary; corolla very large, > 9 cm long 28. I. megalantha
Plant pubescent to subglabrous, hairs appressed; flowers usually in cymes; corolla < 6.5 cm long 48
48 Lower leaves entire, upper leaves usually 3-lobed 10. I. morongii
All leaves divided into 3–5 lobes 11. I. malvaeoides
49 Inflorescence terminal, formed of few-flowered cymes 7. I. malpighipila
Inflorescence of solitary axillary flowers, these occasionally in axillary cymes 50
50 Corollas 6–9 cm long 51
Corollas 5–6 cm long 11. I. malvaeoides
51 Sepals obtuse, mucronate; inner sepals 11–16 mm long 14. I. sp. A
Sepals acute; inner sepals 8–11 mm long 12. I. pseudomalvaeoides

Key A3

Digitate-leaved species with leaves divided to or near the base into 5 or more segments. Excluded are species with all or most leaves 3-lobed or divided to halfway or less.

1 Corolla up to 3 cm long; plants slender annuals or perennials 2
Corolla 3.5–9 cm long; plants perennial 8
2 Corolla 1–1.2 cm long; sepals apiculate; introduced weed in dry areas of Venezuela......... 328. I. costellata
Corolla 1.7–3 cm long; sepals not apiculate 3
3 Perennials from a bulb-like corm; sepals muricate, scarious margined (high altitude Andean species) 4
Annual or perennial lowland herbs lacking a corm-like rootstock; sepals neither muricate, nor prominently scarious-margined; plants not usually occurring above 2500 m 5
4 Leaves imbricate, the segments filiform; sepals outer sepals 4–5 mm long; plant usually erect 288. I. capillacea
Leaves scarcely imbricate, the segments linear 1–3 mm wide; outer sepals 5.5–7 mm long; plant usually decumbent to ascending 287. I. plummerae
5 Peduncle coiled or at least twisted; leaflets all arising from the same origin 6
Peduncle straight or nearly so; leaflets pedate or some forked 7
6 Sepal base abruptly truncate, margin fimbriate below 373. I. tenera
Sepal base, rounded, margin entire, not fimbriate 374. I. heptaphylla
7 Corolla yellow with violet centre; sepals > 7 mm long, acuminate; dry habitats 383. I. longeramosa
Corolla pink; sepals 3–3.5 mm, obtuse; wetlands in Venezuela and Colombia 280. I. pittieri
8 Sepals with a prominent appendage on the abaxial surface (NE Brazil) 90. I. rosea
Sepals lacking an appendage on the abaxial surface 9
9 Leaf petioles with conspicuous pseudo-stipules 392. I. cairica
Leaf petioles clearly lacking pseudo-stipules 10
10 Leaf segments linear to oblong, ±parallel-sided, mostly < 5 mm wide 11
Leaf segments elliptic, ovate or obovate, clearly not parallel-sided 23
11 Corolla glabrous 12
Corolla pubescent 16
12 Sepals > 1.5 cm long 13
Sepals 0.5–1 cm long 14
13 Sepals truncate at base; slender herb, variable in habit but never erect 377. I. pantanalensis
Sepals narrowed at base; erect herb 13. I. theodori
14 Sepals obovate suborbicular, about as long as broad 156. I. platensis
Sepals ovate or oblong, twice as long as broad 15
15 Sepals ovate, apiculate, 5–6 mm long (stream sides) 378. I. subrevoluta
Sepals oblong, rounded, rounded (granite domes) 89. I. graniticola
16 Twining plant 18. I. revoluta
Erect or ascending herbs 17
17 All or most leaf segments less than 3 mm wide 18
All or most leaf segments oblong, not linear 20
18 All leaf segments < 5 cm long 19
Some or all segments 5–7 cm long 15. I. itapuaensis
19 Sepals 5–8 mm, obtuse to rounded; inflorescence usually terminal and cymose in form 17. I. angustissima
Sepals 9–11 mm, acute; inflorescence axillary; flowers solitary in the leaf axils 16. I. fiebrigii
20 Inflorescence terminal, formed of few-flowered cymes 7. I. malpighipila
Inflorescence of solitary axillary flowers, these occasionally in axillary cymes 21
21 Corolla 6–9 cm long 22
Corolla 5–6 cm long 11. I. malvaeoides
22 Sepals obtuse, mucronate; inner sepals 11–16 mm long 14. I. sp. A
Sepals acute; inner sepals 8–11 mm long 12. I. pseudomalvaeoides
23 Sepals > 20 cm long, bracteoles large, persistent, often concealing the calyx 107. I. gigantea
Sepals < 1.5 cm, bracteoles small, caducous, never concealing the calyx 24
24 Corolla and sepals glabrous 25
Corolla and sepals pubescent 29
25 Sepals papery, flat, subacute to mucronate 95. I. killipiana
Sepals coriaceous, convex, rounded 26
26 Inflorescence of compound, many-flowered axillary cymes, 10–30 cm in length (Peru) 158. I. maranyonensis
Inflorescence of simple or doubled axillary cymes, 10 cm long 27
27 Leaf lobes linear-oblong 156. I. platensis
Leaf lobes (oblong-)elliptic 28
28 Leaves large, 5–14 × 6–16 cm (wetlands in tropical lowlands) 157. I. mauritiana
Leaves relatively small, mostly 4–6 × 5–7 cm (mostly dry habitats in the inter-Andean valleys and the Chaco lowlands) 159. I. cheirophylla
29 Leaves digitately lobed to base 3. I. pampeana
Leaves not digitately divided to base 30
30 Corolla almost glabrous; leaves 6–9-palmatisect with elliptic to oblanceolate lobes 1. I. stuckertii
Corolla conspicuously pubescent; leaves 3–5-palmatilobed with ovate lobes 2. I. padillae

Key A4

Species with very long sepals, mostly exceeding 2 cm in length

1 Corolla pure white, the tube narrowly cylindrical, sepals with a long terminal awn 272. I. alba
Corolla pink, blue, or yellowish with a coloured tube, tube not cylindrical; sepals not awned 2
2 Leaves lobed or divided into segments 3
Leaves entire, ovate, cordate 6
3 Leaf divided into linear-filiform segments; erect plant (Paraguay) 13. I. theodori
Leaf segments or lobes broad; trailing or climbing plant 4
4 Leaf divided into 5–10 oblong segments (Brazil) 107. I. gigantea
Leaf lobed, not divided into separate segments 5
5 Leaves and sepals glabrous; corolla purple (Cusco area, Peru) 402. I. cuscoensis
Leaves and sepals hirsute; corolla blue when fresh 236. I. nil
6 Corolla pubescent on the exterior 7
Corolla glabrous on the exterior 9
7 Corolla pink; pedicels very short, < 10 mm long; bracteoles relatively persistent 8
Corolla yellowish with purple tube; pedicels 10–25 mm; bracteoles short, caducous (Venezuela) 109. I. yaracuyensis
8 Peduncles 3–5 cm long; corolla 6–7 cm long (Bolivia and Brazil) 98. I. calyptrata
Peduncles < 1.2 cm; corolla 12 cm long (Peru) 113. I. nivea
9 Sepals obovate to suborbicular; stamens exserted from corolla 269. I. mirandina
Sepals lanceolate or oblong, much longer than broad; stamens included in corolla 10
10 Leaves sagittate with acute auricles; sepals with prominent longitudinal vein 355. I. incarnata
Leaves cordate with rounded auricles; sepals lacking prominent longitudinal veins 11
11 Leaves pubescent (Brazil) 405. I. daturiflora
Leaves glabrous 12
12 Sepals very unequal in size 360. I. paranaensis
Sepals equal or nearly so 13
13 Flowers solitary (rarely paired); stem with scattered long spreading white hairs; corolla pale blue 401. I. clavata
Inflorescence a cyme of up to 7 flowers; stem glabrous; corolla pale lilac 217. I. peruviana

Key A5

Species with coriaceous sepals. Perennial erect, trailing or twining herbs or woody lianas, erect, trailing or twining, stellate hairs sometimes present. Leaves lobed or entire. Sepals coriaceous, convex, subequal, usually glabrous but sometimes indumentum from pedicels extends onto lower half of outer sepals. Corolla glabrous (except I. discolor), funnel-shaped with included stamens or hypocrateriform or suburceolate with exserted stamens. Capsule 4-seeded, seeds commonly with prominent, long marginal hairs.

1 Corolla pubescent on the exterior (Venezuela and Guianas) 172. I. discolor
Corolla glabrous on the exterior 2
2 Stellate (branched) hairs present on leaves and stem 3
Hairs all unbranched 6
3 Stellate hairs conspicuous, unbranched hairs absent or very few 4
Stellate hairs inconspicuous, mixed with and partly concealed by unbranched hairs 5
4 Stellate hairs with long branches 0.5–1.5 mm long 163. I. homotrichoidea
Stellate hairs with short branches <0.5 mm long 162. I. bonariensis
5 Corolla funnel-shaped; stamens included 164. I. oranensis
Corolla hypocrateriform; stamens exserted 165. I. exserta
6 Stems erect; petioles < 1 cm long; leaves linear, oblong or obovate 7
Stems twining or trailing; petioles > 1 cm long; leaves varied but if oblong, plant a liana 10
7 Leaves and stem glabrous 8
Leaves and stem hirsute 9
8 Herb; leaves linear, 1–3 mm wide 169. I. schomburgkii
Subshrub; leaves oblong or oblanceolate, 5–25 mm wide 155. I. franciscana
9 Leaves green, pubescent, imbricate, diminishing in size upwards; corolla weakly lobed 168. I. paulistana
Leaves silvery-sericeous, especially below, not conspicuously imbricate or diminishing in size upwards; corolla lobed 167. I. argentea
10 Leaves 5–7-lobed to near base; vigorous cultivated liana of tropical gardens 211. I. horsfalliae
Leaves entire or lobed, but, if lobed, not lobed to near base or plant herbaceous; naturally growing herbaceous or woody climbers 11
11 Corolla suburceolate or hypocrateriform with a relatively narrow tube, sometimes leafless at anthesis; stamens exserted 12
Corolla funnel-shaped, leaves present at anthesis; stamens included 16
12 Stems and leaves glabrous 13
Stems and leaves hirsute 15
13 Leaves dimorphic, commonly 3-lobed, often absent at anthesis; corolla limb with ovate lobes up to 5 mm long; stem often warted (Venezuela) 171. I. verruculosa
Leaves entire, uniform in shape, present at anthesis; corolla limb very short, the lobes < 3 mm long; stem not warted 14
14 Leaves oblong-elliptic, < 2.5 cm wide (Brazil) 153. I. ana-mariae
Leaves ovate, 4–8 cm wide (Bolivia) 150. I. suburceolata
15 Leaves white canescent on both surfaces, usually absent at anthesis (Brazil) 154. I. longistaminea
Leaves adaxially green, present or absent at anthesis (Bolivia) 165. I. exserta
16 Leaves all conspicuously 3–7-lobed 17
Leaves entire or occasionally with a few leaves shallowly lobed 23
17 Leaves abaxially densely silvery sericeous; corolla campanulate, < 2.5 cm long, white 176. I. eremnobrocha
Leaves abaxially glabrous or thinly pubescent; corolla funnel-shaped > 4 cm long, pink 18
18 All or most leaves 5–7-lobed 19
All or most leaves 3-lobed 22
19 Leaf lobes linear-oblong, not widest in the middle 156. I. platensis
Leaf lobes (oblong-)elliptic, widest in the middle 20
20 Inflorescence of compound, many-flowered axillary cymes, 10–30 cm in length 158. I. maranyonensis
Inflorescence of simple or doubled axillary cymes, 10 cm long 21
21 Leaves large, 5–14 × 6–16 cm; humid tropical lowlands 157. I. mauritiana
Leaves relatively small, mostly 4–6 × 5–7 cm; mostly dry habitats in the inter-Andean valleys and the Chaco lowlands 159. I. cheirophylla
22 Leaves glabrous 160. I. blanchetii
Leaves pubescent 161. I. caloneura
23 Inflorescence with large persistent bracteoles which conceal calyx and capsule 170. I. densibracteata
Bracteoles small, caducous or briefly persistent, never concealing calyx and capsules 24
24 Peduncles and pedicels very short, < 7 mm long 148. I. goyazensis
Peduncles and/or pedicels at least 1 cm long, usually much more 25
25 Leaves glabrous 26
Leaves hirsute at least beneath 31
26 Leaves oblong-ovate to oblong-obovate, base cuneate to weakly cordate; woody lianas of dry country 27
Leaves broadly lanceolate to ovate, base truncate to cordate; plants of relatively moist areas, stems not obviously woody 29
27 Leaves oblong-ovate, base truncate to subcordate (Argentina and Bolivia) 149. I. schulziana
Leaves oblong-elliptic to obovate, base cuneate to attenuate, 0.7–2.5 cm wide (Brazil) 28
28 Leaves with 4–5 pairs of veins, apex rounded to emarginate 152. I. serrana
Leaves with 9–12 pairs of veins, apex acute to obtuse 151. I. pintoi
29 Leaves 10–22 × 9–16 cm, commonly with a distinct angle or tooth on the margin; sepals 9–12 mm long (Southern Brazil) 147. I. austrobrasiliensis
Leaves mostly < 14 × 10 cm long, lacking a distinct marginal angle or tooth; sepals usually < 9 mm long 30
30 Widespread species of lowland forest; leaves ovate, usually entire 145. I. batatoides
Andean species; leaves subdeltoid, often shallowly 3-lobed 146. I. volcanensis
31 Stem and leaves with stiff spreading bulbous white hairs 142. I. pogonocalyx
Stem and leaves variously hirsute but never as above 32
32 Leaf base broadly cuneate, leaves oblong-ovate 143. I. sp . C
Leaf base cordate; leaves ovate, sometimes lobed 33
33 Bracteoles caducous 34
Bracteoles persistent (Amazonia) 166. I. asplundii
34 Lowland species; indumentum usually sparse, stellate hairs absent 145. I. batatoides
Andean species (Bolivia and Argentina); indumentum dense with some stellate hairs 164. I. oranensis

Key A6

Species with a subcylindrical corolla tube and exserted stamens. Perennial or annual herbs of varying habit and leaf shape. Corolla subcylindrical, the tube scarcely widened upwards; stamens exserted.

1 Corolla white or white flushed very pale blue 2
Corolla variously coloured but never white or white flushed bluish 6
2 Corolla suburceolate, the limb very short 423. I. scopulina
Corolla hypocrateriform with a conspicuous limb 3
3 Sepals obtuse; peduncle very long, 22–40 cm 82. I. marcellia
Sepals awned or mucronate; peduncles < 20 cm long 4
4 Outer sepals with long awns 5–12 mm long; stems often with fleshy spines 272. I. alba
Outer sepals mucronate but lacking long awns; stems lacking fleshy spines 5
5 Leaves lanceolate, base rounded to cuneate (Galapagos Islands) 390. I. habeliana
Leaves ovate or suborbicular, cordate (widespread on coasts) 389. I. violacea
6 Sepals terminating in a distinct awn; corolla bright red, yellow or orange; plants annual, slender Go to Key to Quamoclit clade (page 556)
Sepals obtuse or acute, sometimes mucronate, but the mucro < 1 mm long; corolla dark red, pink or purple; perennial herbs, lianas or subshrubs 7
7 Corolla pubescent at least on the exterior 8
Corolla glabrous on theexterior 9
8 Sepals unequal, the inner 16–17 mm long; ovary and capsule hirsute 404. I. sidifolia
Sepals subequal, 10–12 mm long; ovary (and presumably capsule) glabrous 96. I. cavalcantei
9 Leaves lanceolate, up to 1 cm wide (Peru) 425. I . sp. D .
Leaves of varied shape, usually ovate, at least 1.5 cm wide 10
10 Sepals coriaceous, convex; glabrous (Key A5) 11
Sepals varied but nor coriaceous or convex, glabrous or pubescent 14
11 Leaves glabrous 12
Leaves densely hirsute, especially abaxially 13
12 Leaves oblong-elliptic, < 2.5 cm wide (Brazil) 153. I. ana-mariae
Leaves ovate, 4–8 cm wide (Bolivia) 150. I. suburceolata
13 Leaves white canescent on both surfaces, usually absent at anthesis (Brazil) 154. I. longistaminea
Leaves adaxially green, usually present at anthesis (Bolivia) 165. I. exserta
14 Sepals obovate, 1.8–2.5 cm long (Venezuela) 269. I. mirandina
Sepals < 11 mm long, ovate, oblong or lanceolate 15
15 Corolla tube < 3.5 cm long (Peru and Ecuador) 16
Corolla tube > 3.5 cm long (Colombia, Venezuela and Brazil) 17
16 Sepals very unequal, the outer 3–4 mm long 310. I. alexandrae
Sepals subequal 9–10 mm long 309. I. nationis
17 Sepals obtuse to rounded; leaves commonly lobed; stems usually warted (Venezuela) 171. I. verruculosa
Sepals acute, usually mucronate; leaves always unlobed; stems not warted 18
18 Petioles < 2.2 cm; sepals unequal (Brazil) 291. I. dumosa
Petioles > 4 cm; sepals subequal (Venezuela and Colombia) 265. I. retropilosa

Key A7

Species with small flowers, the corolla < 3 cm long

1 Leaves divided to base into 5 or more digitate segments 2
Leaves entire, or, if divided, only 3-lobed, the lateral lobes sometimes forked 8
2 Corolla 1–1.2 cm long; sepals apiculate; introduced weed of dry areas in Venezuela 328. I. costellata
Corolla 1.7–3 cm long; Sepals various (apiculate only in I. longeramosa) 3
3 Perennials from a bulb-like corm; Sepals muricate, scarious-margined (High altitude Andean species) 4
Annual or perennial lowland herbs lacking a corm-like rootstock; sepals neither muricate, nor prominently scarious-margined 5
4 Leaves imbricate, the segments filiform; outer sepals 4–5 mm; plant usually erect 288. I. capillacea
Leaves scarcely imbricate, the segments linear 1–3 mm wide; outer sepals 5.5–7 mm; plant usually decumbent to ascending 287. I. plummerae
5 Peduncle coiled or at least twisted; leaflets all arising from the same origin 6
Peduncle straight or nearly so; leaflets pedate or some forked 7
6 Sepal base abruptly truncate, margin fimbriate below 373. I. tenera
Sepal base, rounded, margin entire, not fimbriate 374. I. heptaphylla
7 Corolla pale yellow with violet centre; sepals > 7 mm long, acuminate, apiculate; dry habitats 383. I. longeramosa
Corolla pink; sepals 3–3.5 mm, obtuse; wetlands in Venezuela and Colombia 280. I. pittieri
8 Corolla pubescent on the exterior 9
Corolla glabrous on the exterior 10
9 Flowers arranged in dense heads surrounded by persistent bracteoles 244. I. neurocephala
Flowers not in dense bracteate heads 311. I. velardei
10 Flowers in bracteolate clusters, the bracteoles 7–25 mm long, persistent 305. I. meyeri
Inflorescence clearly cymose or flowers solitary; bracteoles inconspicuous, often caducous 11
11 Corolla white, cream or yellowish, sometimes with a dark centre 12
Corolla pink 18
12 Leaves 3-lobed 13
Leaves entire 14
13 Outer sepals 13–20 mm, ovate, basally cordate and auriculate; flowers usually solitary 375. I. macedoi
Outer sepals 4–5 mm, oblong, basally cuneate; inflorescence of condensed axillary cymes 176. I. eremnobrocha
14 Corolla c. 0.5 cm long; sepals 2–3 mm long 336. I. minutiflora
Corolla > 1.5 cm long; sepals 5–7 mm long 15
15 Sepals oblong, > 10 mm long 403. I. corymbosa
Sepals ovate or elliptic, < 10 mm long 16
16 Sepals white-margined; capsule strongly rostrate; cymes congested, the pedicels < 5 mm long 382. I. acanthocarpa
Sepals not white-margined; capsule muticous; cymes lax, the pedicels 5–15 mm long 17
17 Annual herb; sepals ovate, acute, often mucronate; corolla 1.5–2.5 cm long (Caribbean) 413. I. obscura
Perennial herb: sepals elliptic, obtuse; corolla 2.3–3.5 cm long (moist forest, often Andean) 87. I. reticulata
18 Leaves 3-lobed with the two laterals forked (Brazil) 384. I. kraholandica
Leaves entire or 3-lobed but, if 3-lobed, the laterals undivided 19
19 Low Andean herb; leaves cuneate, entire, bi- or trilobed 287. I. plummerae
Twining herbs; leaves ovate, cordate or 3-lobed 20
20 Whole plant softly grey-canescent (Bolivia near Brazil) 387. I. deminuta
Plant glabrous or pubescent, but never grey-canescent/tomentellous 21
21 Subshrub with somewhat succulent leaves; plant completely glabrous 340. I. amnicola
Slender herbs, not succulent; plants glabrous or variously hirsute 22
22 Sepals with dark blotches on abaxial surface 281. I. dumetorum
Sepals lacking dark blotches on abaxial surface 23
23 Peduncle passing through sinus of leaf base; sepals 3–5 mm long, corolla blue when fresh 298. I. aristolochiifolia
Peduncle not passing through sinus of leaf base; sepals mostly more than 5 mm long, but, if less, corolla pink when fresh 24
24 Sepals acute, not mucronate or aristate, lanceolate-deltoid; corolla, when fresh, blue with white throat 255. I. marginisepala
Sepals variously shaped (but never lanceolate-deltoid), always mucronate; corolla pink or pink with a dark throat 25
25 Flowers solitary (rarely paired); sepals ovate, gradually narrowed to an aristate point 26
Flowers usually several in axillary cymes; sepals variously shaped but not gradually narrowed to an aristate point 28
26 Completely glabrous trailing herb (Colombia) 357. I. colombiana
Stem, leaves and/or sepals variously hirsute (Bolivia and Brazil) 27
27 Leaves entire; stem glabrous; capsule rostrate 406. I. chiquitensis
Leaves commonly lobed; stem pilose; capsule acute, not rostrate 407. I. melancholica
28 Capsule strongly rostrate; seeds pilose; sepals thick in texture with white margins; leaf auricles commonly acute 382. I. acanthocarpa
Capsule muticious, style rarely persistent; sepals thin in texture, lacking white margins; leaf auricles usually rounded (Batatas Clade) 29
29 Outer sepals broadly oblong-elliptic, usually glabrous; capsule glabrous or hirsute 30
Outer sepals lanceolate or ovate, usually hirsute; capsule usually hirsute 31
30 Ovary and capsule glabrous; capsule compressed 230. I. ramosissima
Ovary and capsule pubescent; capsule conical 231. I. cynanchifolia
31 Corolla < 1.8 cm long 229. I. triloba
Corolla 2–2.5 cm long 228. I. grandifolia

Key A8

Plants with a white or yellow glabrous corolla. Included are tree-like shrubs or lianas with white flowers and dark purplish or pinkish centres, which have not been keyed out earlier.

If sepals with fleshy spines go to Key A1.

If corolla with cylindrical tube and exserted stamens: Go to Key A6.

If corolla < 3 cm long go to Key A7.

If an erect plant with sessile/subsessile leaves go to Key A2.

If plant with coriaceous, convex sepals, go to Key A5.

1 Sepals very unequal, the outer conspicuously shorter than the inner sepals 2
Sepals equal or only slightly unequal 5
2 Stems trailing, often rooting at the nodes 3
Stems twining or clambering over vegetation or arborescent 4
3 Leaves linear or oblong, rectangular or 5-lobed (coastal) 388. I. imperati
Leaves ovate or subreniform 347. I. asarifolia
4 Leaves tomentellous to tomentose; outer sepals 10–12 mm long 94. I. sulina
Leaves usually glabrous; outermost sepal <3 mm long 381. I. anisomeres
5 Small trees 6
Lianas or perennial somewhat woody climbers 7
6 Leaves and sepals completely glabrous 117. I. pauciflora
Abaxial leaf surface and sepals thinly pubescent 119. I. wolcottiana
7 Liana leafless at anthesis, flowers borne towards the apex of slender branches, many metres high 116. I. juliagutierreziae
Plant with leaves present at anthesis, the flowers borne in axillary cymes, corymbs or racemes 8
8 Corolla large, 9–12 cm long 9
Corolla < 6.5 cm long 10
9 Corolla white with dark pinkish-purple centre; leaves abaxially greyish or whitish with prominent reticulate venation 106. I. paradae
Corolla pure white or with a very pale pink centre; leaves abaxially pale green, not conspicuously reticulate-veined 85. I. inaccessa
10 Peduncles short, < 1.5 cm long so inflorescence appearing compact 11
Peduncles 1.5–8 cm long 12
11 Sepals densely pubescent; pedicels 3–5 mm long 110. I. chrysocalyx
Sepals usually glabrous; pedicels 7–27 mm long 400. I. lindenii
12 Bracteoles 2–3 cm long, persistent, asperous-pilose 105. I. longibracteolata
Bracteoles < 1.5 cm long, usually caducous, glabrous 13
13 Corolla 2.5–3.5 cm long 14
Corolla 3.5–5 cm long 15
14 Sepals 10–14 mm long, spreading in fruit 403. I. corymbosa
Sepals 5–7 mm long, not spreading in fruit 87. I. reticulata
15 Sepals obtuse or rounded, not mucronate; inflorescence commonly compound 16 Sepals mucronate or very acute; inflorescence of simple axillary cymes 17
16 Pedicels very long, 1.5–2.5 cm; corolla campanulate, pendulous; plant glabrous 371. I. syringiifolia
Pedicels mostly less than 1.5 cm long; corolla funnel-shaped, not pendulous; plant glabrous or hirsute 86. I. saopaulista
17 Slender annual herb with yellow flowers, usually somewhat hirsute at least abaxially on the leaves; white latex absent 412. I. ochracea
Robust perennial with white flowers, sometimes with pink centre, almost completely glabrous; white latex usually abundant (Bolivia) 223. I. lactifera

Key A9

Plants with flowers in subcapitate inflorescences. Inflorescence pedunculate but flowers on reduced pedicels so clustered in a head-like inflorescence, the bracteoles often persistent.

1 Corolla subcylindrical, suburceolate (Brazil) 423. I. scopulina
Corolla funnel-shaped with expanded limb 2
2 Corolla white; peduncle up to 40 cm long; trailing liana 82. I. marcellia
Corolla pink; peduncles usually < 10 cm long 3
3 Leaves, stem and sepals grey-tomentose 4
Leaves, stem and sepals glabrous or pubescent 5
4 Bracteoles ovate-rhomboid, 2–4 mm wide; corolla with a few hairs at tips of midpetaline bands 353. I. amazonica
Bracteoles filiform, < 1 mm wide; corolla pubescent 69. I. argentinica
5 Bracteoles forming a spathe-like involucre around the flowers 6
Bracteoles narrow or broad but not forming a spathe-like involucre 7
6 Bracteoles basally united to form a boat-shaped involucre, paler basally but not prominently veined 419. I. involucrata
Bracteoles free at the base, not forming a boat-like structure, pale green with prominent dark veins 244. I. neurocephala
7 Corolla glabrous 8
Corolla pubescent at least in bud 386. I. eriocalyx
8 Bracteoles inconspicuous, caducous or somewhat persistent, up to 5 mm long 9
Bracteoles conspicuous, persistent, > 5 mm long 10
9 Sepals ovate, very shortly mucronate, abaxially pubescent, inconspicuously veined 422. I. fasciculata
Sepals oblong to oblong-elliptic, acuminate, conspicuously mucronate, ciliate-margined or glabrous, prominently veined 220. I. batatas
10 Leaves glabrous; bracteoles narrowly ovate, boat-shaped; inflorescence hispid-pilose 240. I. spruceana
Leaves usually hirsute, at least abaxially; bracteoles linear, not boat-shaped; inflorescence pubescent but not hispid-pilose 234. I. indica

Key A10

Trailing, climbing or twining plants not in Keys A1–9 with corolla > 3.5 cm long, pubescent on the exterior. Buds should be checked carefully as pubescence is more obvious at this stage. On mature flowers check near the apex of the midpetaline bands.

1 Leaf base truncate, rounded, cuneate or attenuate, never cordate or sagittate; plant trailing 2
Leaf base cordate or sagittate; plant erect, climbing, twining or trailing 21
2 Leaves all or mostly 3-lobed 3
Leaves all simple, rarely a few weakly 3-lobed 8
3 Leaves white-tomentose or sericeous at least on the lower surface 4
Leaves pubescent or pilose but not whitish on either surface 6
4 Flowers solitary 68. I. pseudocalystegia
Flowers in cymes 5
5 Inner sepals obtuse; adaxial leaf surface green, thinly pilose; corolla 7–8 cm long (Bolivia) 63. I. opulifolia
Inner sepals acute; adaxial leaf surface thinly floccose-tomentose; corolla c. 4.5 cm long (Brazil) 52. I. malvaviscoides
6 Sepals obtuse to subacute 21. I. delphinioides
Sepals finely acuminate 7
7 Flowers solitary; corolla 8.5–9.5 cm long 28. I. megalantha
Flowers in cymes; corolla 5.5–6.5 cm long 20. I. acutisepala
8 Flowers solitary or paired 9
At least some inflorescences of 3- or more-flowered cymes 12
9 Leaves ovate to suborbicular 23. I. chodatiana
Leaves oblong to oblong-elliptic 10
10 Sepals finely acuminate (Paraguay) 19. I. valenzuelensis
Sepals obtuse to acute 11
11 Sepals acute; leaves broadly oblong, > 1.5 cm wide 32. I. subspicata
Sepals obtuse; leaves narrowly oblong, < 1.2 cm wide 36. I. ensiformis
12 Leaves white-tomentose or sericeous abaxially 13
Leaves hirsute but not whitish abaxially 17
13 Leaves white-sericeous on both surfaces 26. I. altoparanaensis
Leaves distinctly discolorous, the adaxial surface green even if with some white hairs 14
14 Leaves broadly ovate to elliptic, scarcely longer than broad 15
Leaves narrowly ovate to oblong-ovate, 2–3 times longer than broad 16
15 Inflorescence from upper leaf axils only; leaves subrhomboid with petioles < 2 cm long (Andean Bolivia) 56. I. mendozae
Inflorescence clearly axillary; leaves ovate with petioles 1–4.5 cm long (Southern Brazil) 22. I. uruguayensis
16 Leaves asperous-pilose (Brazil) 51. I. langsdorfii
Leaves white woolly, not asperous (Argentina) 27. I. lanuginosa
17 Leaves all < 8 mm wide; sepals finely acuminate, 12–14 mm long 37. I. attenuata
Leaves all > 15 mm wide; sepals obtuse or acute, up to 12 mm long 18
18 Leaves glabrous or thinly pubescent 19
Leaves conspicuously sericeous or pubescent, at least beneath 20
19 Petioles < 1 cm long; leaves completely glabrous; cymes simple (Bolivia) 25. I. psammophila
Petioles up to 4.5 cm long; leaves glabrous or thinly pubescent abaxially; cymes usually compounded (Argentina) 24b. I. nitida subsp. krapovickasii
20 Leaves sericeous; sepals acute (Argentina) 24a. I. nitida subsp. nitida
Leaves pubescent; sepals obtuse to acute (Brazil) 21. I. delphinioides
21 Leaves mostly 3-lobed to about halfway 22
Leaves unlobed or a few leaves 2–3-lobed 27
22 Sepals 15–20 mm long, pale green, minutely puberulent 5. I. cardenasiana
Sepals < 15 mm long, grey-tomentose or pubescent 23
23 Sepals pilose with spreading hairs; plant of wetlands 399. I. rubens
Sepals appressed hairy to sericeous; plants of dry habitats 24
24 Leaves dimorphic with some entire and some lobed on the same plant; inflorescence subterminal 4. I. prolifera
Leaves all lobed on the same plant; inflorescence clearly axillary 25
25 Lobes acute to acuminate 63. I. opulifolia
Lobes rounded to obtuse, mucronate 26
26 Flowers solitary or subsessile at the apex of a long peduncle 68. I. pseudocalystegia
Flowers in cymes, clearly pedicellate 67. I. mucronifolia
27 Leaves conspicuous grey- or white-tomentose or sericeous abaxially 28
Leaves green abaxially, not strongly grey- or white-tomentose 53
28 Inflorescence borne on long peduncles 20–42 cm in length 29
Inflorescence borne on peduncles < 25 cm long; corolla pink 30
29 Corolla white; stamens shortly exserted 82. I. marcellia
Corolla pink; stamens included 100. I. descolei
30 Flowers all or mostly solitary (rarely up to 3) 31
Flowers in axillary cymes of 3 or more flowers 34
31 Leaves mostly > 7 × 6 cm 32
Leaves very small, < 5 × 5 cm 33
32 Trailing herb; sepals acute, not markedly accrescent in fruit (Bolivia) 57. I. gypsophila
Liana; sepals rounded to obtuse, accrescent to 2.8 cm (Galapagos) 418. I. tiliifolia
33 Bracteoles caducous; pedicels 6–15 mm (Venezuela, Guyana) 172. I. discolor
Bracteoles persistent; pedicels very short, < 5 mm long (Brazil) 44. I. geophilifolia
34 Sepals relatively large, > 14 mm long, especially in fruit; bracteoles usually > 15 mm long 35
Sepals <13 mm long (sometimes more in glabrous leaved I. chondrosepala); bracteoles short, usually < 12 mm long 39
35 Leaves tomentellous adaxially; capsule large, 1.5–2 cm 36
Leaves glabrous adaxially; capsule unknown 37
36 Bracteoles persistent adpressed to calyx; leaves grey-tomentose adaxially 98. I. calyptrata
Bracteoles caducous, not adpressed to calyx; leaves green-tomentose adaxially 108. I. brasiliana var. subincana
37 Outer sepals 14–16 mm long 38
Outer sepals 18–25 mm long 396. I. pearceana
38 Leaves large, > 9 cm long; peduncles long, mostly > 15 cm long (Cultivated) 393. I. nervosa
Leaves small, < 6 cm long (Peru); peduncles < 4.5 cm 114. I. mathewsiana
39 Sepals short, < 8 mm long 40
Sepals 8–15 mm long 42
40 Sepals rounded, lacking black glands at base (Andes south to Peru) 84a. I. carnea subsp. carnea
Sepals acute to apiculate, commonly with dark glands at base 41
41 Vegetative parts all shortly and finely sericeous; ovary hirsute 397. I. velutinifolia
Vegetative parts, subglabrous, pubescent or appressed pilose but never uniformly sericeous; ovary glabrous 61. I. megapotamica
42 Sepals with conspicuous spreading hairs 43
Sepals appressed hairy, tomentose or sericeous 44
43 Bracteoles caducous; corolla c. 5 cm long (Wet places) 399. I. rubens
Bracteoles somewhat persistent; corolla c. 8 cm long (Dry places, Bolivia) 70. I. longibarbis
44 Sepals glabrous or nearly so 45
Sepals tomentose, sericeous or uniformly pubescent 46
45 Cymes simple; sepals ovate to elliptic 73. I. jalapa
Cymes commonly compounded and inflorescence subracemose or corymbose; sepals oblong or oblong-obovate 394. I. abutiloides
46 Leaves obtuse with a 3 mm apical mucro 66. I. walteri
Leaves not as above 47
47 Bracteoles 12–20 mm long, persistent till after the flowers have fallen 69. I. argentinica
Bracteoles usually < 10 mm long, usually deciduous at anthesis 48
48 Leaves dimorphic, some lobed, some entire; inflorescence subtermina 4. I. prolifera
Leaves all entire; inflorescence axillary 49
49 Abaxial leaf surfaces with long appressed hairs; cymes usually few-flowered (Colombia) 64. I. macarenensis
Abaxial leaf surface tomentose but hairs not appressed nor long 50
50 Corolla large 9–11 cm long (Ecuador, Colombia, Venezuela) 73. I. jalapa
Corolla 4.5–7 cm long 51
51 Sepals oblong; inflorescence often formed on leafy branchlets 395. I. sericosepala
Sepals ovate; inflorescence of leafless cymes 52
52 Sepals acute, not mucronate, eglandular, peduncles and pedicels usually short so inflorescence crowded (Central Brazil) 65. I. sericophylla
Sepals mucronate, usually with two large basal glands; inflorescence lax (Southern Andes) 45. I. hieronymi
53 Corolla < 4 cm long (Ecuador and Peru) 311. I. velardei
Corolla > 5 cm long 54
54 Stem and inflorescence bearded with yellowish hairs; bracteoles persistent; pedicels < 10 mm long (Ecuador) 245. I. harlingii
Stem and inflorescence not bearded with yellowish hairs; bracteoles persistent or not; pedicels mostly > 10 mm long 55
55 Stem with fleshy teeth; corolla limb deeply lobed; violet with white tube 270. I. parasitica
Stem unarmed; corolla limb at most weakly lobed; tube coloured 56
56 Sepals lanceolate, much longer than broad 57
Sepals ovate to elliptic, only slightly longer than broad 58
57 Flowers solitary (rarely paired); peduncle < 5 mm long 417. I. chapadensis
Flowers in cymes; peduncles well-developed, usually exceeding 10 mm 416. I. regnellii
58 Flowers solitary (very rarely up to 3); sepals strongly accrescent and enveloping the capsule 418. I. tiliifolia
Flowers several in cymes, rarely reduced to single flowers 59
59 Sepals with a prominent swollen abaxial appendage (Bolivia) 58. I. appendiculata
Sepals lacking a prominent swollen abaxial appendage 60
60 Trailing perennial with stout stem; leaves undulate to dentate (very dry inter-Andean valleys of Bolivia and Argentina) 71. I. lilloana
Twining or climbing perennials, stems stout to slender; leaves occasionally lobed but not undulate or dentate 61
61 Corolla very large, 7–12 cm long; sepals mostly > 10 mm long 62
Corolla 4–6.5 cm long; sepals mostly < 8 m long 65
62 Sepals glabrous; stem often winged 72. I. subalata
Sepals thinly to densely pubescent; stems unwinged 63
63 Stems minutely spinulose, thinly pilose with long white hairs; abaxial surface of leaves glabrous apart from highlighted veins (Bolivia) 46. I. spinulifera
Stems smooth, lacking spinules and long white hairs; veins not highlighted on abaxial leaf surface 64
64 Sepals 10–15 mm long (Central America, Caribbean and Ecuador) 73. I. jalapa
Sepals 8–10 mm long (Brazil) 59. I. cearensis
65 Sepals rounded to obtuse; base of calyx truncate (Brazil) 62. I. decipiens
Sepals acute; base of calyx cuneate to rounded 66
66 Inflorescence clearly cymose; corolla pink; old stems not corky 61. I. megapotamica
Inflorescence often subracemose; corolla usually white; old stems corky (Chaco) 60. I. vivianae

Key A11

Trailing and twining plants not in Keys A1–9 with a glabrous corolla, > 3.5 cm long.

1 Creeping seashore plant with fleshy stems and leaves; leaves apically retuse; pedicel persistent on fallen capsule 339. I. pes-caprae
Plant not growing on seashores; leaves not apically retuse and rarely fleshy; pedicel not persistent on fallen capsule 2
2 Night flowering species with dull lilac, somewhat salver-shaped corolla; stems commonly armed with soft fleshy spines 271. I. muricata
Day flowering species with pink corolla; stems lacking soft spines 3
3 Leaf base cuneate to attenuate; trailing plants of the Cerrado 4
Leaf base truncate, cordate, hastate or sagittate; plants of varying habit and habitat 9
4 Leaves linear or narrowly oblong, attenuate at base, the petiole not clearly differentiated 5
Leaves oblong to ovate, cuneate at base, the petiole distinct from the lamina 6
5 Sepals narrowed at base; leaves linear, 0.5–1 mm wide; stem, pedicels and leaves glabrous 365. I. graminifolia
Sepals with a broad truncate base; leaves narrowly oblong, at least 2 mm wide; stem, pedicels and leaves with long white hairs 420. I. dolichopoda
6 Sepals abaxially muricate 7
Sepals abaxially smooth 8
7 Leaves oblong or ovate; plant only woody basally 345. I. procurrens
Leaves oblong-elliptic to suborbicular; woody subshrub 344. I. coriacea
8 Flowers solitary (rarely paired); inflorescence leafless 366. I. procumbens
Flowers in cymes, often somewhat leafy 367. I. rupestris
9 Peduncle fused with petiole for part of its length 92. I. connata
Peduncles and petioles not fused 10
10 Sepals with a prominent abaxial appendage 379. I. bahiensis
Sepals smooth, ribbed or muricate but lacking a prominent abaxial appendage 11
11 Sepals with prominent abaxial muricate ribs 12
Sepals abaxially smooth 14
12 Bracteoles linear 3 × 0.5 mm; corolla c. 10 cm long 343. I. parvibracteolata
Bracteoles 8–20 × 3–15 mm; corolla 2.5–8 cm long 13
13 Annual herb; corolla 2.5–3.5 cm long 341. I. fimbriosepala
Perennial herb; corolla 5.5–8 cm long 342. I. setifera
14 Sepals conspicuously truncate or cordate at base, often with a lateral tooth 15
Sepals narrowed or rounded at base, lacking teeth 16
15 Sepals ovate, cordate; leaves entire or shallowly 3-lobed 376. I. apodiensis
Sepals deltoid, truncate; leaves usually 3–5-lobed to near the base, rarely ovate-deltoid 377. I. pantanalensis
16 Sepals very unequal in length, the outer conspicuously shorter than the inner 17
Sepals all equal or slightly unequal in length 29
17 Leaves and stem white-tomentellous (Peru) 115. I. pulcherrima
Leaves and stem not white-tomentellous 18
18 Abaxial surface of sepals commonly muricate; plants of seasonally wet areas 19
Abaxial surface of sepals smooth; plants of dry or moist habitats 20
19 Leaves ovate, sagittate 346. I. paludicola
Leaves subreniform, hastate 347. I. asarifolia
20 Outermost sepal very short, < 3 mm long; plant glabrous 233. I. cryptica
Outermost sepal > 5 mm long; plant glabrous or pubescent 21
21 Leaves tomentose on both surfaces, cordate 144. I. mirabilis
Leaves glabrous or thinly pubescent, sagittate or cordate 22
22 Sepals all < 10 mm long, the margins usually white 380. I. squamosa
Inner sepals usually > 10 mm long, often somewhat scarious but not distinctly white-margined 23
23 Inner sepals < 12 mm long; leaves ovate to deltoid 24
Inner sepals > 13 mm long; leaves varied in shape 25
24 Inner sepals acuminate; corolla < 3. 5 cm long (Colombia) 357. I. colombiana
Inner sepals obtuse to rounded, mucronate; corolla 4–6 cm long 356. I. maurandioides
25 Sepals relatively large, the inner 15–28 mm long;; leaves usually rounded at apex 360. I. paranaensis
Inner sepals < 16 mm long; leaves narrowed to an obtuse or acute apex 26
26 Leaves oblong, the margins undulate 361. I. variifolia
Leaves linear, lanceolate or ovate, the margin entire 27
27 Leaves narrowly oblong, the base hastate to sagittate; peduncles very short, < 2 mm long 362. I. tacuaremboensis
Leaves ovate-deltoid or linear, sagittate; peduncles mostly more than 2 cm long 28
28 Corolla lobes terminating in a distinct mucro 5–6 mm long; lamina narrowly ovate-deltoid with prominent deltoid auricles 359. I. mucronatoproducta
Corolla unlobed or lobes not terminating in a distinct mucro; lamina linear, similar to the auricles 358. I. aequiloba
29 Flowers solitary; leaves deltoid with very slender pedicels 370. I. longirostra
Flowers several in axillary cymes; leaves ovate, cordate, not strikingly deltoid or with disproportionately slender pedicels 30
30 Sepals relatively short, all < 12 mm long 31
Sepals relatively long, some > 12 mm long 40
31 Perennial or annual herbs; sepals always mucronate, usually of papery texture; corolla usually with a dark centre, 3.5–5.5 cm long; leaves lobed or not; ovary and capsule hirsute or not Batatas Clade (Species 218–233)
Perennial herbs or subshrubs; sepals mucronate or not but never papery in texture; corolla usually lacking a dark centre, 3.5–9 cm long; leaves unlobed; ovary and capsule glabrous 32
32 Stem, petioles or abaxial leaf surface tomentose, pubescent or puberulent 33
Plant completely glabrous 36
33 Leaves dentate (Bolivia) 299. I. odontophylla
Leaves entire or undulate 34
34 Peduncle passing through sinus of leaf base; corolla pale blue (Bolivia) 300. I. huayllae
Peduncle not passing through sinus of leaf base; corolla pink 35
35 Leaves with overlapping auricles; stamens held at corolla mouth, 2.5 cm long; seeds lanate 88. I. tarijensis
Leaf auricles not overlapping; stamens held within corolla tube, 4–5 cm long; seeds tomentellous 289. I. jujuyensis
36 Corolla blue with cream tube; sepals lanceolate, acute with white margins 37
Corolla pink (rarely white), the tube similar or darker in colour; sepals of varied shape but mostly mucronate, always lacking white margins 38
37 Corolla < 4 cm long (Andean Argentina and Bolivia) 255. I. marginisepala
Corolla 5.5–7 cm (Mexico, but widely cultivated elsewhere) 257. I. tricolor
38 Leaves usually sagittate; aquatic herb rooting at nodes on mud 391. I. aquatica
Leaves ovate, cordate; subshrubs climbing to several metres 39
39 Corolla 4–5.5 cm long 340b. I. amnicola subsp. chiliantha
Corolla < 3.5 cm long 340a. I. amnicola subsp. amnicola
40 Leaves white-tomentose abaxially 41
Leaves variously hirsute or glabrous, but if ±tomentose abaxially, indumenm not white or bracts linear, persistent 43
41 Pedicels 1–4 mm, bracteoles persistent, appressed to calyx 99. I. veadeirosii
Pedicels mostly > 10 mm, not appressed to calyx, caducous 42
42 Corolla 10–12 cm long; marginal hairs on seeds up to 20 mm long 104. I. magna
Corolla 5–8 cm long; hairs on seeds up to 5 mm long 108. I. brasiliana
43 Bracteoles linear to oblong, persistent; sepals commonly tapered to an elongated apex; leaves 3-lobed or, less commonly, entire; ovary trilocular; often weedy hirsute species of disturbed places (Pharbitis Clade) 44
Bracteoles filiform to linear, caducous; sepals varied but lacking an elongated apex; leaves unlobed; ovary bilocular, glabrous or hirsute herbs or subshrubs 49
44 Sepals deltoid with a distinct truncate base 242. I. pubescens
Sepals linear-oblong, narrowed at base 45
45 Sepals 15– 35 mm long, tapering to a long point, lanceolate with a broad base, often conspicuously pilose at base; leaves 3-lobed 46
Sepals < 20 mm long, linear-oblong, pubescent but not conspicuously pilose near base; leaves simple or 3-lobed 47
46 Sepals with fleshy recurved tips (southern USA, adventive elsewhere) 237. I. hederacea
Sepals with erect, herbaceous tips (very widespread) 236. I. nil
47 Leaves very large, 11–20 × 7–20 cm; corolla 7–9 cm long; bracteoles usually caducous (Bolivia and Peru) 247. I. magnifolia
Leaves < 11 × 11 cm; corolla 4–6 cm; bracteoles always persistent (widespread) 48
48 Vegetative parts softly pubescent; sepals oblong or lanceolate; corolla usually pink; leaves usually unlobed; flowers not clustered 238. I. purpurea
Vegetative parts usually hirsute but not softly pubescent; sepals ovate; corolla usually bluish-purple; leaves commonly lobed; flowers commonly clustered 234. I. indica
49 Pedicels and sepals with long shaggy hairs 105. I. longibracteolata
Pedicels and sepals glabrous or shortly pubescent 50
50 Sepals acuminate to a fine point 51
Sepals obtuse, rounded or retuse 52
51 Sepals prominently veined; leaves sagittate; plant glabrous 355. I. incarnata
Sepals not prominently veined; leaves cordate; plant thinly pubescent 247. I. magnifolia
52 Stems winged (caatinga of Bahia) 91. I. pterocaulis
Stems not winged (moist forest) 53
53 Corolla bluish or greenish or yellow; sepals oblong-lanceolate; peduncles very short, usually < 1 cm long 400. I. lindenii
Corolla pink; sepals oblong, ovate or suborbicular; peduncles usually > 1 cm long or flowers borne on leafy side shoots 54
54 Corolla tube narrow, often constricted below limb; sepals opaque, commonly reddish; inflorescence often compound, much branched 352. I. philomega
Corolla broadly funnel-shaped, not constricted upwards; sepals somewhat transparent, pale green; inflorescence of simple cymes 369. I. chondrosepala

B. Keys to Central and North American species

This key includes all species from continental North America from Panama northwards. For plants from the Caribbean islands, go to Key C and for plants from Hawaii, go to Key D.

Several North American species are notable for having dentate leaves, often in the form of one or two lateral teeth on otherwise entire leaves. The following species are noted as having dentate leaves, at least to some degree: Ipomoea tastensis, I. jicama, I. noctulifolia, I. schaffneri, I. ignava, I. stans, I. jacalana, I. tacambarensis, I. acanthocarpa, I. rupicola, I. calcicola, I. dumetorum (at least sometimes).

Note. Options in Keys B1 to B8 should be considered before proceeding to Keys B9–10.

Key B1: Species with oblong, lanceolate or elliptic leaves, the base narrowed, cuneate to rounded, margin entire or toothed, sometimes pinnatifid, or pinnate.

Key B2: Species with leaves divided digitately to, or near to the base, into five or more free or nearly free lobes or segments.

Key B3: Species with soft fleshy spines/protuberances on the sepals.

Key B4: Species with a subcylindrical corolla tube and (usually) exserted stamens

Key B5: Species with small flowers, the corolla < 3 cm long (or calyx < 5 mm long)

Key B6: Species with white, cream or yellowish flowers > 3 cm long

Key B7 Species with very long sepals, mostly exceeding 1.8 cm in length

Key B8: Plants with subcapitate inflorescences.

Key B9: Trailing, climbing or twining plants with pubescent or hirsute sepals < 1.8 cm long

Key B10. Trailing, climbing or twining plants with glabrous sepals <1.8 cm long.

Key B1

Species with oblong, lanceolate or elliptic leaves, the base narrowed, cuneate to rounded, margin entire or toothed, sometimes pinnate or pinnatifid. Leaves never cordate, hastate, sagittate or truncate or palmately lobed or palmately divided into leaflets. Stems commonly erect, less commonly trailing or climbing.

1 Leaves pinnatifid or strongly dentate 2
Leaves entire or obscurely dentate, serrate or crenate 6
2 Anthers exserted; leaves with pseudo-stipules 312. I. quamoclit
Anthers included; leaves lacking pseudo-stipules 3
3 Leaves oblong with lyrate-dentate margin, usually abaxially pubescent 4
Leaves pinnatifid with narrow segments 1–2 mm wide, glabrous 5
4 Flowers solitary or paired from the leaf axils; sepals unequal; petioles < 5 mm long 276. I. stans
Inflorescence of terminal and axillary cymes with 5–15 flowers; sepals subequal; petioles 2–4.5 cm long 277. I. tacambarensis
5 Leaf segments 1–6 cm long; peduncles 3–12 cm long at anthesis; corolla white or pale lilac 278. I. ancisa
Leaf segments 0.3–2.5 cm long; peduncles 0.8–3.5 cm at anthesis; corolla purplish-blue 279. I. sescossiana
6 Low, often prostrate plants of high altitudes; stems short usually < 20 cm long; sepals muricate; leaves often dimorphic 7
Erect or climbing plants; stems > 20 cm long; sepals smooth; leaves all similar in form 8
7 Corolla 5–5.5 cm long; sepals 6–10 mm long; leaves 2–10 cm long, commonly dimorphic with some simple, some forked and, occasionally, some lobed 286. I. madrensis
Corolla 2–3 cm long; sepals 4–6 mm long; leaves < 2 cm long, all of the same form 287. I. plummerae forma adiantifolia
8 Corolla glabrous on the exterior 9
Corolla pubescent on the exterior at least in bud 15
9 Leaves oblong-elliptic or ovate; plants decumbent, climbing or twining 10
Leaves oblong or lanceolate; plants erect 13
10 Leaves abaxially appressed pilose, silvery in colour 179. I. steerei
Leaves glabrous 11
11 Woody liana; bracteoles 15–26 mm long, oblong-elliptic; peduncles very short, 2–8 mm long 174. I. robinsonii
Perennial herbs, woody at base; bracteoles < 3 mm long; peduncles up to 7 cm long 12
12 Corolla pink, trumpet-shaped (United States) 349. I. shumardiana
Corolla orange or yellow, funnel-shaped (Mesoamerica) 173. I. aurantiaca
13 Sepals very unequal, the outer 10–16 mm long, the inner 16–23 mm long 93. I. longifolia
Sepals subequal, 5–12 mm long 14
14 Leaves pubescent, 4–8 × 1.5–2.5 cm 128. I. petrophila
Leaves glabrous, 3–10 × 0.5 cm 348. I. leptophila
15 Peduncles very short, <5 mm long 16
Peduncles >1.5 cm long 17
16 Leaves, 1 cm long; sepals 7–10 mm long, obtuse 129. I. lenis
Leaves 2–3.5 cm long; sepals 12–16 mm long, acuminate 130. I. durangensis
17 Twining plant; leaves finely acuminate, well-spaced; corolla pink or lilac 78. I. kruseana
Erect undershrub; leaves acute or obtuse, imbricate; corolla white 131. I. ciervensis

Key B2

Species with leaves palmately divided into free or almost free leaflets. This key includes species where the leaflets are pedatisect. All species have glabrous corollas.

1 Sepals elliptic to obovate, obtuse or rounded, coriaceous; robust lianas or perennials 2
Sepals oblong, lanceolate or ovate, commonly acuminate and apiculate; plants mostly slender, annual or perennial herbs 3
2 Corolla red, > 4 cm long; cultivated woody liana 211. I. horsfalliae
Corolla greenish-white, <3.5 cm long; native perennial of Mesoamerica 178. I. heterodoxa
3 Corolla ±salver-shaped; anthers strongly exserted; sepals awned 313. I. fissifolia
Corolla ±funnel-shaped; anthers included; sepals lacking a subterminal awn 4
4 Corolla 4.5–7 cm long, pink or white; leaves with or without pseudo-stipules 5
Corolla usually < 4.5 cm, pink, white or yellow; leaves lacking pseudo-stipules 8
5 Decumbent or ascending plant with short stems, commonly < 10 cm long; leaves lacking pseudo-stipules, usually dimorphic with some palmately lobed and some entire or bifid 286. I. madrensis
Twining plants, stems usually much more than 25 cm long; leaves of one kind, with or without conspicuous pseudo-stipules 6
6 Cylindrical basal part of corolla > 2 cm in length; leaves without conspicuous pseudo-stipules 285. I. tenuiloba
Cylindrical basal part of corolla very short, < 5 mm long; leaves usually with conspicuous pseudo-stipules 7
7 Annual herb; leaves with up to 14 linear or ensiform leaflets 332. I. diegoae
Perennial herb; leaves usually with 5 oblong-elliptic leaflets 392. I. cairica
8 Outer sepals with cordate base and prominent soft spines on abaxial surface 333. I. sororia
Outer sepals neither basally cordate nor with soft spines on adaxially surface 9
9 Peduncle coiled or twisted; sepals obtuse 374. I. heptaphylla
Peduncle straight or suppressed; Sepals acute or acuminate 10
10 Plants erect 5–20 cm high, not twining; leaf segments filiform, <1 mm wide 288. I. capillacea
Plants with twining or trailing stems; leaf segments at least 2 mm wide 11
11 Corolla < 1.2 mm long 328. I. costellata
Corolla > 1.5 cm long 12
12 Corolla entirely yellow 329. I. chamelana
Corolla pink, white or bluish 13
13 Leaves twice divided, the palmate lobes pinnatifid 331. I. perpartita
Leaf segments simple, not pinnatifid 14
14 Cylindrical basal part of corolla very short, often < 5 mm 15
Cylindrical basal part of corolla elongated, often > 10 mm long 285. I. tenuiloba
15 Outer sepals usually muricate, glabrous, obtuse to acute; root a globose tuber; corolla deep pink; leaf segments obtuse 287. I. plummerae
Outer sepals smooth, glabrous or pubescent, acute to acuminate; root a small tap root; corolla pale lilac; leaf segments acute 334. I. ternifolia

Key B3

Plants with sepals covered in soft slightly fleshy spines or protuberances

1 Spines and protuberances present only on the sepals 2
Spines present on petioles, peduncles and/or stem as well as on the sepals 216. I. setosa
2 Sepals with abundant spreading soft spines, resembling fleshy trichomes 3
Sepals with few to many fleshy protuberances, wings or similar structures, not resembling fleshy trichomes 4
3 Sepals up to 35 mm long; peduncles 0–0.4 cm long; pedicels 2–4 cm long 410. I. silvicola
Sepals 12–15 mm long; peduncles 0.5–8 cm long; pedicels 0.8–2.1 cm long 408. I. crinicalyx
4 Pedicels short, < 4.5 mm; corolla 2.5–3 cm long; peduncle winged 372. I. decemcornuta
Pedicels elongate, > 15 mm long; corolla 5–8 cm long; peduncle unwinged 5
5 Flowers usually numerous, cymes often much branched; corolla pubescent in bud and at tips of midpetaline bands 414. I. pedicellaris
Flowers usually solitary, rarely paired, inflorescence simple; corolla glabrous even in bud 6
6 Peduncles 4.5–7.5 cm long; pedicels notably stouter than peduncle; sepals c. 8 mm long 415. I. tentaculifera
Peduncles < 4 cm long; pedicels similar to peduncles in width; sepals 12–14 mm long 132. I. lozanii

Key B4

Corolla tube cylindrical for at least half its length, often to the base of the limb; stamens equal or nearly so, anthers exserted or held at mouth of corolla.

1 Leaves pinnate; pseudo-stipules present 312. I. quamoclit
Leaves not pinnate but if pinnatifid, pseudo-stipules absent 2
2 Sepals with a distinct subterminal awn; corolla red, orange or yellow Go to the Quamoclit Clade (312–327)
Sepals lacking a subterminal awn or, if awn present; corolla pure white or blue 3
3 Corolla white, blue or pale lilac 4
Corolla pink or red 16
4 Corolla tube cylindrical to below the limb 5
Corolla tube cylindrical for about half its length, then gradually expanded in upper half 8
5 Sepals terminating in a prominent awn 272. I. alba
Sepals acute or obtuse, sometimes with a short mucro but never terminating in a long awn 6
6 Sepals 16–23 mm long; anthers weakly exserted or included; sea shore species 389. I. violacea
Sepals <9 mm; anthers clearly exserted; inland species 7
7 Peduncle furnished with prominent setae at base; corolla limb undulate; sepals acute, mucronate 421. I. discoidea
Peduncle glabrous at base; corolla limb distinctly 5-lobed; sepals obtuse 138. I. macdonaldii
8 Corolla pubescent on the exterior at least in bud 9
Corolla glabrous on the exterior even in bud 11
9 Sepals obtuse, equal; leaves weakly lobed, abaxially pubescent at least on the veins (Mexico) 10
Sepals aristate, unequal; leaves entire, glabrous (Costa Rica) 274. I. magniflora
10 Flowers solitary; peduncle < 2.5 cm long; sepals 13–16 mm long 77. I. zimmermanii
Flowers in cymes; peduncles very long, 11–20 cm; sepals 25–40 cm long 248. I. ampullacea
11 Corolla blue orlilac; stems armed with soft spines; sepals with an aristate tip 271. I. muricata
Corolla white, occasionally pale lilac; stems unarmed; sepals sometimes mucronate but never aristate 12
12 Sepals < 7 mm long; anthers scarcely exserted 13
Sepals > 10 mm long; anthers strongly exserted 14
13 Flowers solitary; leaves entire; corolla bluish (drying pink) 307. I. expansa
Inflorescence formed of cymes with up to 7 flowers; leaves 3-lobed; corolla white 136. I. lottiae
14 Leaves with prominent lateral teeth; sepals 2–3 cm long 297. I. tastensis
Leaves entire or palmately lobed; sepals <1.6 cm long 15
15 Corolla pale blue; flowers solitary 262. I. gilana
Corolla pure white; flowers usually several 273. I. santillanii
16 Corolla limb short and inconspicuous (except I. electrina), the tube cylindrical 17
Corolla limb formed of broad obovate lobes, the tube often not strictly cylindrical 21
17 Flowers enclosed within two conspicuous persistent bracteoles forming a spathe-like inflorescence 338. I. bracteata
Flowers naked, bracteoles inconspicuous, often caducous 18
18 Exterior of the corolla conspicuously sericeous or pubescent 181. I. concolor
Exterior of the corolla glabrous or nearly so 19
19 Corolla lobes linear, > 15 mm long 294. I. electrina
Corolla lobes very short, ovate to elliptic, c. 5 mm long 20
20 Pedicels and sepals pubescent 180. I. conzattii
Pedicels and sepals glabrous 182. I. tehuantepecensis
21 Sepals broadly obovate, 18–25 × 12–16 mm (Panama) 269. I. mirandina
Sepals lanceolate, ovate or oblong, < 6 mm wide 22
22 Leaves sagittate 284. I. caudata
Leaves ovate-cordate 23
23 Limb clearly lobed, the lobes short, c. 1.5 cm diameter 293. I. tubulata
Limb subentire, 3.5–5 cm diameter 24
24 Petiole and peduncle fused for part of their length, peduncle usually passing through leaf sinus; calyx usually concealed by folded lamina 291. I. dumosa
Petiole and peduncle free to their base; peduncle not passing through leaf sinus; calyx not concealed by folded leaf 25
25 Sepals lanceolate, 3–5 times longer than broad, unequal, the outer noticeably shorter than the inner 266. I. chenopodiifolia
Sepals ovate, only slightly longer than broad, subequal 290. I. purga

Key B5

Species with small flowers; this includes species with a calyx less than 5 mm long or a corolla less than 3 cm long. Mostly slender herbs but includes a few species of liana habit.

1 Leaves palmatisect into separate segments Go to Key B2
Leaves entire or lobed 2
2 Sepals very short, < 4 mm long 3
Sepals > 4 mm long 5
3 Corolla purple; sepals with 3 distinctive wings/ protuberances I. decemcornuta
Corolla yellow; sepals smooth, unwinged 4
4 Corolla 4–5 mm long, not obviously lobed; stems pilose 336. I. minutifolia
Corolla 25–30 mm long, deeply lobed; stems glabrous or nearly so 335. I. microsepala
5 Ovary and capsule pubescent Go to key to Batatas Clade (218–232)
Ovary and capsule glabrous 6
6 Sepals 10–15 mm long, narrowly lanceolate, nearly always with long, spreading stiff hairs; corolla blue 258. I. barbatisepala
Sepals glabrous or with a few short hairs, if more than 10 mm long, not narrowly lanceolate; corolla cream or pink 7
7 Corolla cream-coloured, ± campanulate; inflorescence often developing into a raceme-like structure; stems woody 8
Corolla pink (rarely white), funnel-shaped; inflorescence of axillary cymes; stems herbaceous except at base 9
8 Sepals 5–7 mm long, deciduous in fruit 87. I. reticulata
Sepals 10–14 mm long, often persistent and speading in fruit 403. I. corymbosa
9 Plant vigorous, somewhat fleshy, clearly perennial, completely glabrous; sepals oblong-elliptic, mucronate 340. I. amnicola
Plant relatively slender, not fleshy, annual or short-lived perennial; sepals not as above 10
10 Leaves strap-shaped (Florida) 232. I. tenuissima
Leaves variously shaped but never strap-shaped 11
11 Low perennial, decumbent, with short stems < 10 cm long; leaves cuneate 287. I. plummerae
Twining annual (?always) herbs, the stems usually at least 1 m long 12
12 Outer sepals obovate, mucronate; capsule depressed-globose, muticous 230. I. ramosissima
Outer sepals oblong-lanceolate to oblong-ovate; capsule ovate, rostrate 13
13 Sepals lanceolate or ovate, acute, the margins whitish, scarious 14
Sepals not as above 15
14 Corolla blue with white tube; sepals lanceolate, 2–4 mm wide; pedicels relatively long, 1–3 cm; leaves lacking a lateral tooth 256. I. cardiophylla
Corolla pink (rarely white); sepals ovate, 3.5–7 mm wide; pedicels 2–5 mm long; leaves commonly with a lateral tooth 382. I. acanthocarpa
15 Peduncle passing through leaf sinus; sepals often muricate, sometimes pubescent, never with dark spots 298. I. aristolochiifolia
Peduncle not passing through leaf sinus; sepals smooth, glabrous, the abaxial surface with dark spots 281. I. dumetorum

Key B6

Plants with white, cream or yellowish flowers more than 3 cm in length, often much more, the throat occasionally dark.

1 Small trees or erect, woody, often multi-stemmed shrubs, often leafless at anthesis Go to key to the Arborescens Clade (Species117–126)
Twining or trailing herbs or lianas 2
2 Stamens exserted; corolla hypocrateriform or salverform or nearly so Go to Key B4
Stamens included; Corolla funnel-shaped or campanulate 3
3 Corolla campanulate, not more than 3.5 cm long 4
Corolla funnel-shaped, hypocrateriform or salver-shaped, usually much more than 3.5 cm long 5
4 Sepals 5–7 mm long, deciduous in fruit 87. I. reticulata
Sepals 10–14 mm long, often persistent and spreading in fruit 403. I. corymbosa
5 Prostrate seashore plant rooting at the nodes; leaves shortly oblong, linear, lanceolate or 3–5-lobed, small, 1.5–3 × 0.8–2 cm 388. I. imperati
Climbing herbs or lianas of inland areas; leaves ovate, mostly large or absen t 6
6 At least some sepals 13 mm or more in length 7
All sepals < 13 mm in length 12
7 Corolla and sepals tomentose or pubescent on the exterior 8
Corolla and sepals glabrous on the exterior 9
8 Trailing herb of coastal regions of the United States; inflorescence clearly axillary Liana of Mexico and Central America; inflorescence arising on short shoots 79. I. praecana
9 Leaves 3-lobed; sepals aristate; inflorescence paniculate 330. I. ramulosa
Leaves entire; sepals muticous or at most shortly mucronate; inflorescence of axillary cymes 10
10 Cymes borne on long peduncles usually > 5 cm long 259. I. chiriquensis
Cymes very shortly pedunculate; the peduncles usually < 1 cm long 11
11 Pedicels very short, cymes dense, subcapitate; bracteoles conspicuous, persistent 112. I. riparum
Pedicels 2–4 cm long, cymes relatively lax; bracteoles inconspicuous, caducous 400. I. lindenii
12 Bracteoles 1.5–2.5 cm long, oblong or oblong-elliptic, persistent; corolla relatively large, 7–8 cm long 174. I. robinsonii
Bracteoles relatively small and inconspicuous, < 5 mm long, usually linear, filiform or squamose: corolla varied in size, often < 7 cm long 13
13 Corolla orange or yellow; leaves ovate, unlobed, the base truncate 173. I. aurantiaca
Corolla white or cream, sometimes with dark throat or blue-flushed; leaves ovate, usually cordate, sometimes lobed, sometimes absent at anthesis 14
14 Corolla white with pink throat; sepals with prominent veins on abaxial surface; leaves often pandurate (United States) 350. I. pandurata
Corolla white with a dark centre; sepals lacking prominent veins on abaxial surface; leaves entire, shallowly lobed; rarely pandurate 15
15 Outermost sepal much shorter than inner sepals, <5 mm long 16
Sepals equal or nearly so, or if somewhat unequal, outer sepal at least 5 mm long 17
16 Peduncles 5–10 cm long; bracteoles caducous; outer sepal c. 3 mm long, green 381. I. anisomeres
Peduncles < 1 cm long; bracteoles persistent; outer sepal c. 5 mm long, whitish-green 111. I. pochutlensis
17 Sepals oblong to oblong-obovate, not coriaceous nor convex; flowers usually solitary (rarely up to 3); leaves typically very small < 4.5 cm long (if flowers several and sepals oblong-lanceolate see I. lindenii) 133. I. hartwegii
Sepals ovate to elliptic, coriaceous, usually convex; flowers solitary or in cymes; some leaves > 4.5 cm long or leaves absent 18
18 Corolla sericeous; plant leafless at anthesis, stem and leaves velutinous 140. I. pruinosa
Corolla glabrous or almost so; Plant leafy or leafless at anthesis; stem and leaves glabrous or variously hirsute but not velutinous 19
19 Stem, leaves, (and typically) pedicels and sepals pilose with stiff spreading, bristly hairs 141. I. suaveolens
Hairs, if present, neither spreading nor bristly 20
20 Sepals distinctly unequal; outer sepals oblong to oblong-elliptic, inner sepals up to 12 mm long; indumentum with at least some branched hairs 135. I. scopulorum
Sepals equal or slightly unequal, varied in shape but about as broad as long; plants glabrous or with simple hairs 21
21 Corolla hypocrateriform 22
Corolla funnel-shaped 23
22 Leaves lobed; stem, leaves and sepals pubescent; peduncles < 3 cm long 136. I. lottiae
Leaves entire; stem, leaves and sepals glabrous except on the leaf margins; peduncles > 10 cm long 138. I. macdonaldii
23 Woody lianas; leaves entire, never lobed 24
Perennial herb, leaves lobed or entire, or, if woody, absent at anthesis 25
24 Leaves broadly ovate, 7–14 × 6–10 cm, pubescent 134. I. cuprinacoma
Leaves obscurely puberulent 118. I. populina
25 Plant leafless at anthesis 139. I. pseudoracemosa
Leaves present at anthesis 26
26 Leaves pubescent, usually lobed; peduncles < 1 cm long 27
Leaves glabrous; peduncles > 3 cm long 28
27 Leaves entire, usually glabrous; sepals oblong-lanceolate, 5–18 mm long; corolla often flushed violet 400. I. lindenii
Leaves commonly lobed, usually pubescent; sepals ovate to orbicular up to 8 mm long; corolla white 137. I. proxima
28 Peduncles up to 13 cm long; leaves basally truncate; plant of central Mexico 139. I. pseudoracemosa form
Peduncles usually 3–6 cm long; leaves basally cordate, flowers often pink; plant of southern Mexico 145. I. batatoides

Key B7

Plants with long sepals > 18 mm in length.

1 Sepals covered in soft spines 410. I. silvicola
Sepals lacking soft spines 2
2 Sepals terminating in a prominent awn; corolla white, the tube long, narrow, cylindrical 272. I. alba
Sepals acute or obtuse, sometimes with a short mucro but never terminating in a long awn; corolla tube not long, narrow and cylindrical, white, blue or pink 3
3 Liana with winged stem; leaves palmatilobed; peduncles < 11 mm long; corolla subcampanulate, magenta 127. I. kahloae
Plants of varied habit but stems unwinged and corolla never magenta; peduncles usually > 15 mm long 4
4 Small trees or lianas; corolla white 5
Perennial or annual herbs; corolla pink or blue, rarely white 6
5 Liana 79. I. praecana
Tree 119. I. wolcottiana
6 Leaves with marginal teeth 7
Leaves entire or lobed but lacking marginal teeth 8
7 Corolla 9–12 cm long, white; anthers exserted 297. I. tastensis
Corolla 5–6 cm, pale pink; anthers included 296. I. jicama
8 Sepals distinctly pubescent or tomentose 9
Sepals glabrous or nearly so 18
9 Corolla glabrous on the exterior 10
Corolla pubescent, sericeous on tomentose on the exterior 15
10 Sepals with distinct white margins 11
Sepals uniformly green 12
11 Leaves entire 261. I. orizabensis
Leaves deeply lobed 261b. I. orizabensis subsp. collina
12 Flowers 1(–2); leaves usually 3–5 lobed; corolla pink 13
Flowers usually of 2 or more flowers; leaves entire or shallowly lobed; corolla blue or pink 14
13 Corolla 7–9 cm long; sepals lanceolate, cuneate, much longer than broad 243. I. lindheimeri
Corolla < 5 cm long; sepals ovate, cordate, c. twice as long as broad 242. I. pubescens
14 Corolla pink (rarely white or blue); sepals oblong-lanceolate, obtuse or acute; leaves entire or 3–5-lobed 238. I. purpurea
Corolla blue with a white tube (drying pink): sepals ovate with an elongate apex, notably accrescent in fruit 236. I. nil
15 Base of sepals truncate or subcordate; leaves palmately lobed or entire 253. I. laeta
Base of sepals cuneate to rounded; leaves entire or 3-lobed 16
16 Flowers in cymes of 3–5; stigma 3-lobed; capsule 15 mm wide, not enclosed by accrescent sepals 17
Flowers usually solitary, rarely 2–3; stigma bilobed; capsule subglobose, 20–25 mm wide, enclosed by accrescent sepals (near the sea) 418. I. tiliifolia
17 Leaves entire; bracteoles deciduous 250. I. mairetii
Leaves 3-lobed; bracteoles persistent 249. I. temascaltepecensis
18 Abaxial surface of outer sepals with prominent longitudinal veins 19
Abaxial surface of outer sepals lacking prominent longitudinal veins 21
19 Bracteoles prominent, persistent; veins on sepals denticulate; corolla pink 20
Bracts minute, deciduous; veins on sepals smooth; corolla white with a pink throat 350. I. pandurata
20 Annual herb; corolla 2.5–3.5 cm long 341. I. fimbriosepala
Perennial herb; corolla 5.5–8 cm long 342. I. setifera
21 Inflorescence with large boat-shaped, chartaceous, oblong-elliptic bracteoles 2–2.5 × 0. 5–1.2 cm 22
Inflorescence with small, inconspicuous, often caducous bracteoles 23
22 Corolla glabrous 251. I. invicta
Corolla pubescent 252. I. lambii
23 Sepals broadly (ob)ovate, elliptic or suborbicular, scarcely longer than broad 24
Sepals ovate, lanceolate or oblong, distinctly longer than broad 25
24 Corolla hypocrateriform; anthers exserted (Panama) 269. I. mirandina
Corolla funnel-form; stamens included 352. I. philomega
25 Sepals narrowly lanceolate, acuminate; leaves lobed 254. I. thurberi
Sepals oblong, oblong-lanceolate or oblong-ovate; leaves usually entire 26
26 Sepals with prominent white hyaline margins 261. I. orizabensis
Sepals lacking distinct white hyaline margins 27
27 Flowers solitary (rarely paired); inner sepals 22–30 mm long (Mexico southwards) 28
Flowers several to many in cymes; inner sepals usually < 22 mm long (United States) 350. I. pandurata
28 Flowers blue; stem thinly pilose with long white hairs 401. I. clavata
Flowers pink; stem glabrescent (puberlous when young) 295. I. bernoulliana

Key B8

Inflorescence subcapitate, flowers in compact heads, never solitary; bracteoles usually persistent.

1 Corolla pubescent, at least in bud; bracteoles somewhat chartaceous 2
Corolla glabrous, even in bud; bracteoles not chartaceous 4
2 Corolla, stem, bracteoles and leaves sparsely hairy 252. I. lambii
Corolla, stem, bracteoles and leaves densely hairy 3
3 Outer bracteoles ovate to suborbicular, 7–20 × 7–24 mm, pale green with darker veins 244. I. neurocephala
Outer bracteoles lanceolate to ovate, 20–25 × 5 mm, uniformly green 246. I. villifera
4 Corolla white 112. I. riparum
Corolla pink or violet 5
5 Bracteoles linear/filiform, < 1 m wide 305. I. meyeri
Bracteoles expanded, ovate or oblong > 2 mm wide 6
6 Leaves forming a spathe-like structure around the terminal inflorescence 268. I. mcvaughii
Leaves not forming a spathe-like structure around the flowers; inflorescence clearly axillary 7
7 Bracteoles up to 2.5 cm long; sepals 20–23 mm long (Mexico) 251. I. invicta
Bracteoles up to 10 mm long; sepals 11–20 mm (widespread) 234. I. indica

Key B9

Plants not in Keys B1–8 with pubescent, pilose or tomentose sepals, < 18 mm long.

1 Small erect trees or shrubs 2
Perennial or annual herbs 3
2 Flowers pink; sepals < 6 mm long, densely tomentellous 84b. I. carnea subsp. fistulosa
Flowers white; Sepals > 5.5 mm long, sparsely pubescent Go to Arborescens Clade (Species117–126)
3 Corolla glabrous on the exterior 4
Corolla pubescent on the exterior at least when in bud 13
4 Sepals abruptly terminating in a distinct mucro; slender, usually annual herbs Go to the Batatas Clade (Species 218–233)
Sepals obtuse or narrowed into a terminal mucro, margin not clearly ciliate 5
5 Leaves dentate with conspicuous teeth 6
Leaves entire 7
6 Leaf margin with numerous small teeth; sepals foliose, 1–4.5 cm long 275. I. jacalana
Leaf margin with few large teeth; bracteoles small, 3–7 mm 302. I. schaffneri
7 Sepals pilose with conspicuous long spreading hairs 8
Sepals pubescent or very shortly pilose 11
8 Sepals lanceolate, acuminate, > 9 mm long; corolla pink or blue 9
Sepals elliptic, obtuse, < 8 mm long; corolla white 141. I. suaveolens
9 Sepals glabrous in the upper half; leaves always entire; ovary bilocular 306. I. mitchelliae
Sepals hirsute to apex; leaves entire or lobed; ovary trilocular 10
10 Corolla blue, drying pink; sepals recurving, the tips strongly accrescent in fruit; leaves usually 3-lobed 237. I. hederacea
Corolla pink; sepals remaining erect, not strikingly accrescent in fruit; leaves entire or lobed 238. I. purpurea
11 Pedicels 10–35 mm long, so inflorescence usually lax; leaves thinly pubescent 12
Pedicels very short, < 12 mm, so inflorescence dense; leaves densely appressed white-pilose to tomentose abaxially 177. I. peteri
12 Corolla pink; flowers in cymes; stamens included 261. I. orizabensis
Corolla pale blue; flowers solitary; stamens exserted (United States) 262. I. gilana
13 Leaves absent at anthesis; corolla white with pink midpetaline bands 140. I. pruinosa
Leaves present at anthesis; corolla pink or lilac 14
14 Leaves polymorphic, some entire, some digitately 7-lobed 75. I. leonensis
Leaves all ± of the same shape, none digitately 7-lobed 15
15 Leaves slightly paler abaxially but essentially green on both surfaces 16
Leaves distinctly discolorous; the abaxial surface whitish and strongly contrasting with the greenish adaxial surface 20
16 Leaves small, < 5 cm long and wide, margins undulate or dentate 17
Leaves mostly > 5 cm long, margins entire 18
17 Sepals ovate, acuminate, subequal, all 12–13 mm long 239. I. zacatecana
Sepals oblong to oblong-elliptic, obtuse, unequal, the outer 8–10 mm long 76. I. rupicola
18 Sepals oblong-lanceolate three times longer than broad, < 4 mm wide 416. I. regnellii
Sepals ovate to elliptic, > 4 mm wide 19
19 Flowers in cymes of 3 or more flowers; seeds long-pilose 73. I. jalapa
Flowers solitary; seeds densely pubescent 260. I. decasperma
20 Sepals with prominent white margins; leaves deeply 3-lobed 241. I. calcicola
Sepals lacking prominent white margins; Leaves entire or shallowly lobed 21
21 Perennial herbs; sepals with spreading hairs 22
Lianas; sepals sericeous with appressed hairs 23
22 Outer sepals < 10 mm long, grey-sericeous 263. I. leucotricha
Outer sepals > 10 mm long, shortly pilose 399. I. rubens
23 Corolla urceolate, the tube greenish with pinkish midpetaline bands; seeds densely woolly 24
Corolla funnel-shaped, uniformly pink; seeds pubescent 25
24 Sepals 5–7 mm long; corolla 3–3.5 cm long 81. I. bombycina
Sepals 11–15 mm long; corolla c. 4.5 cm long 80. I. gesnerioides
25 Bracteoles papery, persistent, 2.5–6 cm long; flowers several in cymes; sepals 12–16 mm long 393. I. nervosa
Bracteoles small, caducous; flowers usually solitary, rarely up to 3; sepals strongly accrescent to 4 cm in fruit 418. I. tiliifolia

Key B10

Plants not in Keys B1–8 with glabrous sepals < 18 mm long; i.e. sepals without hairs, but some species may have fleshy teeth

1 Prostrate seaside plant, rooting at the nodes; corolla white; flowers solitary 388. I. imperati
Plants of various habits but if maritime, corolla pink, solitary or in cymes 2
2 Prostrate seaside plant with pink flowers and large somewhat fleshy rounded to retuse leaves 339. I. pes-caprae
Usually twining inland plants but if maritime, not as above 3
3 Corolla (buds) sericeous or pubescent 4
Corolla glabrous on the exterior even in bud 6
4 Leaves conspicuously white sericeous on lower surface (Panama) 394. I. abutiloides
Leaves green abaxially 5
5 Corolla 6–8 cm long, pink; stem always lacking soft spines; flowers numerous; sepals often winged or muricate 414. I. pedicellaris
Corolla 2.5–4 cm long, bluish with white tube; stem often with scattered soft spines; flowers few; sepals abaxially smooth, occasionally with a few hairs 270. I. parasitica
6 Sepals aristate with a long attenuate mucro up to 7 mm in length; corolla lilac or bluish, open at night; stem muricate with soft spines 271. I. muricata
Sepals varied in shape, sometimes acuminate but not aristate; corolla pink or white, not lilac; stem not muricate with soft spines 7
7 Peduncles very short, < 1.5 cm long; corolla dark violet (or creamy); sepals elongate, with scarious margins 400. I. lindenii
Peduncles short or long, but if short, corolla not dark violet or creamy, nor sepals elongate with scarious margins 8
8 Pedicels very short, < 1.5 cm, calyx concealed or not by leaves or bracteoles 9
Pedicels at least 1.5 cm long, usually much longer, the calyx exposed 18
9 Flowers in compact cymes with small, inconspicuous bracteoles 10
Flowers solitary or, if numerous, with conspicuous large bracteoles 12
10 Leaves abaxially white, sericeous or tomentose 11
Leaves abaxially green 305. I. meyeri
11 Leaves entire 175. I. isthmica
Leaves deeply lobed 176. I. eremnobrocha
12 Bracteoles ovate to suborbicular, spathe-like, completely enclosing the calyx 13
Bracteoles not spathe-like, calyx concealed by leaves or large bracteoles 14
13 Inflorescence pedunculate, axillary 337. I. suffulta
Inflorescence terminal on the branches, subsessile 268. I. mcvaughii
14 Corolla white; flowers numerous 112. I. riparum
Corolla pink; flowers in cymes of 1–4 15
15 Corolla hypocrateriform; stamens exserted, flowers in cymes of 1–5 flowers 291. I. dumosa
Corolla funnel-shaped; stamens included; flowers solitary 16
16 Leaves partially enclosing the calyx; peduncle and petiole fused basally; leaves 1–6 cm long, acuminate 292. I. seducta
Leaves distant from calyx; peduncle and petiole not fused; Leaves < 2 cm long, obtuse 17
17 Leaves rounded in outline, the margin with large teeth 267. I. noctulifolia
Leaves broadly ovate, margin entire or obscurely dentate 304. I. eximia
18 Leaves with large marginal teeth 303. I. ignava
Leaves entire or lobed but lacking marginal teeth 19
19 Sepals very unequal in length 20
Sepals equal or only slightly unequal in length 26
20 Flowers solitary (rarely paired); leaves strongly sagittate; corolla gradually widened from a narrow base 21
Flowers several in cymes, rarely solitary; leaves varied in shape but, if sagittate, corolla not widened as above 22
21 Corolla funnel-shaped, 4–7 cm long; sepals oblong-elliptic, 3–7 mm wide, smooth 351. I. sagittata
Corolla very narrowly funnel-shaped, 6–10 cm long; sepals lanceolate to oblong, < 3 mm wide, muricate 301. I. elongata
22 Sepals up to 10 mm long, abaxially smooth 23
Inner sepals 8–15 mm long; outer sepals often transversely muricate 25
23 Corolla pink; outermost sepal at least 5 mm long 380. I. squamosa
Corolla white; outermost sepal 2–5 mm long 19
24 Outer sepals < 3 mm long, obtuse to rounded; corolla 5–6 cm long 381. I. anisomeres
Outer sepals 2–5 mm acute; corolla 3.5–4 cm long 308. I. puncticulata
25 Leaves ovate, sagittate; corolla pink 7–8.5 cm long 346. I. paludicola
Leaves subreniform, usually hastate; Corolla, white with dark centre or pale pink, 5–6 cm long 347. I. asarifolia
26 Aquatic plant rooting at the nodes; leaves usually hastate or sagittate 391. I. aquatica
Terrestrial plants, usually climbing, not rooting at nodes 27
27 Flowers solitary, rarely paired 28
Inflorescence formed of cymes of 3 or more flowers 31
28 Sepals with dark blotches, ovate, 3–8 mm long 29
Sepals lacking dark blotches, oblong or, if ovate > 12 mm long 30
29 Corolla 4–6 cm long, reddish-purple with pale tube 283. I. miquihuanensis
Corolla 2.5–4.5 cm long, blue 282. I. simulans
30 Sepals oblong to oblong-obovate, < 10 mm long, abaxially smooth; corolla white or pale pink 133. I. hartwegii
Sepals ovate, 12–14 mm long, abaxially often with a few teeth; corolla reddish-purple 132. I. lozanii
31 Outer sepals scarious, papery in texture 218. I. splendor-sylvae
Outer sepals varied in texture, but not papery 32
32 Sepals oblong-deltoid, dark green with white margin; corolla blue with yellowish throat and white tube 257. I. tricolor
Sepals and corolla not as above 33
33 Sepals thin in texture, flat, conspicuously mucronate 34
Sepals coriaceous, elliptic, usually obtuse and convex, inconspicuously mucronate 35
34 Flowers in a lax cyme 221. I. tiliacea
Flowers in a subumbellate pedunculate inflorescence 220. I. batatas
35 Leaves palmately lobed 157. I. mauritiana
Leaves entire 36
36 Corolla pink 37
Corolla white 134. I. cuprinacoma
37 Sepals broadly oblong to elliptic, rounded, not more than twice as long as broad, usually < 8 mm long 145. I. batatoides
Sepals lanceolate to oblong-lanceolate, c. 3 times longer than broad, usually 8–12 mm long 266. I. chenopodiifolia subsp. bellator

C. Key to Caribbean Island species

1 Erect undershrub, usually cultivated 84. I. carnea subsp. fistulosa
Trailing or twining herbs or lianas 2
2 Leaves pinnate 312. I. quamoclit
Leaves entire, lobed or digitately divided into leaflets 3
3 Leaves borne on short brachyblasts, very small, <3 cm long 4
Leaves not borne on brachyblasts, usually much > 3 cm long 7
4 Leaves digitately lobed (Cuba, Jamaica) 5
Leaves reniform, bilobed, or some leaves trifoliate, the terminal leaflet bilobed (Puerto Rico and Lesser Antilles) 6
5 Leaves divided into 3 leaflets; corolla red (Cuba) 201. I. microdonta
Leaves divided mostly into 5–7 leaflets; corolla with green tube and pale pink limb (Jamaica) 204. I. tenuifolia
6 Corolla funnel-shaped (Virgin Islands to Barbuda) 202. I. eggesiana
Corolla hypocrateriform (Puerto Rico) 203. I. steudelii
7 Leaves palmately divided almost to or completely to the base, the leaflets free or joined only near the base 8
Leaves entire, or shallowly lobed but, if palmately 3-lobed, divided to not more than three quarters of their length and bracteoles persistent, prominent 21
8 Sepals lanceolate, oblong, acute to mucronate, clearly longer than broad, not coriaceous 9
Sepals elliptic to obovate, occasionally mucronate but never acute, about as broad as long, coriaceous 12
9 Corolla 4–5 cm long, pink 10
Corolla < 3 cm long, pink or creamy yellow 11
10 Petioles usually with pseudo-stipules at base; leaflets lanceolate to oblong-lanceolate 392. I. cairica
Petioles lacking pseudo-stipules; leaflets linear to narrowly oblong (Cuba, Trinidad) 378. I. subrevoluta
11 Corolla creamy yellow with dark centre; peduncle usually straight; sepals acuminate and mucronate 383. I. longeramosa
Corolla pink; peduncle twisted and commonly coiled; sepals obtuse 374. I. heptaphylla
12 Corolla white or greenish-white, sometimes with pale pink lobes 13
Corolla pink or red 15
13 Leaflets filiform; corolla small, < 2 cm long (Hispaniola) 207. I. nematoloba
Leaflets relatively broad oblong-elliptic, ovate or elliptic; corolla 3–5 cm long 14
14 Leaflets 7.5–14 cm long; leavesalways 3-lobed (Jamaica) 212. I. ternata
Leaflets < 7 cm long, leaces 3–5-lobed (Hispaniola) 215. I. clausa
15 Corolla 2.5–4 cm; sepals 4–6 mm long; (Hispaniola) 16
Corolla > 4 cm long; some or all sepals > 7 mm long 17
16 Sepals red-margined; leaflets oblong 214. I. digitata
Sepals green margined; leaflets oblanceolate 213. I. desrousseauxii
17 Leaflets completely sessile or partially fused at base; plant cultivated or growing in disturbed places 18
Leaflets with a short but distinct basal petiole; plants growing in natural situations 19
18 Woody liana, cymes commonly compound 211. I. horsfalliae
Trailing or climbing herb; cymes usually simple 157. I. mauritiana
19 Corolla 5–6 cm long; leaflets usually broadest towards the base or in the middle, mostly oblong-elliptic (Jamaica) 210. I. lineolata
Corolla 4–5 cm long; leaflets mostly oblong, oblanceolate or obovate, rather narrow and broadest near apex 20
20 Leaflets up to 6.5 × 2.2 cm long; peduncles stout < 4 cm long (Cuba and Bahamas) 208. I. carolina
Leaflets up to 11 × 3.5 cm long; peduncles (Hispaniola) 209. I. furcyensis
21 Corolla pubescent on the exterior (best seen in bud) 22
Corolla glabrous on the exterior 30
22 Weedy annual herb with subsessile cymes, the peduncles < 10 mm long; corolla 7–9 mm long 398. I. eriocarpa
Annual or perennial herbs, relatively robust in habit; inflorescence pedunculate; corolla > 2.5 cm long 23
23 Sepals 5–7 mm long 24
Sepals at least 8 mm long, often much more in fruit 25
24 Sepals about as broad as long, uniformly pubescent; corolla pink, 6–7 cm long 84a. I. carnea subsp. carnea
Sepals longer than broad, nearly glabrous but with a few scattered hairs; corolla blue with white tube, 2.5–4 cm long 270. I. parasitica
25 Bracteoles caducous, absent at anthesis; corolla relatively large, > 5 cm long, usually much longer 26
Bracteoles relatively persistent, conspicuous, 1.5–4 cm long; corolla < 5 cm long 28
26 Corolla white, cream or bluish; sepals narrowly ovate, much longer than broad; sepals and leaves usually glabrous (Jamaica) 400. I. lindenii
Corolla pink; sepals broadly ovate or ovate elliptic, not much longer than broad; sepals and leaves pubescent or sericeous 27
27 Woody liana; flowers solitary (rarely to 3); sepals strongly accrescent in fruit and enclosing the capsule 418. I. tiliifolia
Perennial herb; flowers usually in cymes of 3–5 flowers (sometimes more); sepals not strongly accrescent in fruit 73. I. jalapa
28 Leaves borne in fascicles; flowers subsessile, borne on peduncles < 1.5 cm long 205. I. lachnaea
Leaves solitary, petiolate; flowers in pedunculate cymes 29
29 Bracteoles papery, pale yellow-green; sepals 12–16 mm long, elliptic to obovate (cultivated or an escape) 393. I. nervosa
Bracteoles not papery, reddish to mauve in colour; sepals 18–25 mm, ovate to lanceolate (Cuba and Hispaniola) 354. I. racemosa
30 Corolla 8–11 cm long; anthers at least weakly exserted 31
Corolla < 8 cm long; anthers included or exserted 32
31 Sepals lanceolate, terminating in a long awn-like structure 272. I. alba
Sepals elliptic to suborbicular, obtuse, sometimes shortly mucronate 389. I. violacea
32 Sepals pubescent or tomentose; perennials with coriaceous, obtuse sepals and densely sericeous or pubescent leaves 33
Sepals glabrous or, if hirsute, plants annual and weedy, leaves glabrous or pubescent; sepals acute to strongly mucronate 39
33 Corolla yellow-green; indumentum of stellate hairs (Hispaniola) 206. I. luteoviridis
Corolla pink or purple; indumentum of unbranched hairs (Cuba) 34
34 Stamens strongly exserted; corolla hypocrateriform 35
Stamens included; corolla funnel-shaped 37
35 Plant leafless at anthesis; inflorescence of axillary clusters; sepals reddish, pubescent near base only (Cuba) 193. I. praecox
Plant leafy at anthesis; onflorescece cymose; sepals uniformly tomentose, grey 36
36 Leaves basally subcordate; bracteoles linear-lanceolate, not foliose (Cuba 195. I. jalapoides
Leaves basally cuneate; bracteoles obovate to oblanceolate, foliose (Cuba) 192. I. argentifolia
37 Leaves 3-lobed (Cuba) 188. I. passifloroides
Leaves entire 38
38 Sepals pubescent only near base; flowers several in cymes (Cuba) 196. I. montecristina
Sepals uniformly tomentose; flowers solitary (Cuba) 194. I. calophylla
39 Sepals elliptic to obovate, obtuse to rounded, coriaceous, glabrous; plants perennial 40
Sepals varied, usually lanceolate, ovate or oblong, acute to acuminate, often mucronate, glabrous or hirsute; plants annual or perennial 54
40 Corolla greenish-yellow to white 41
Corolla red, purple or pink 45
41 Leaves dentate, abaxially pubescent (Cuba) 186. I. erosa
Leaves entire or lobed but not dentate; glabrous 42
42 Stamens exserted; leaves lobed with acute lobes (Cuba) 184. I. cubensis
Stamens included; leaves entire or variously lobed 43
43 Corolla 3.5–6 cm long; seeds with long marginal hairs 44
Corolla 1.5–1.7 cm long; seeds uniformly pilose (Cuba) 185. I. merremioides
44 Leaves ovate to ovate elliptic, rarely shallowly lobed (Cuba) 183. I. alterniflora
Leaves usually deeply lobed or palmately divided into leaflets but if entire, ovate-deltoid (Hispaniola) 215. I. clausa
45 Leaves pubescent or sericeous 46
Leaves glabrous 49
46 Leaves green, pubescent or pilose abaxially; sepals often reddish 47
Leaves silvery sericeous abaxially; sepals not reddish 48
47 Leaves large, 4–16 cm long; peduncles 3–7 cm long 190. I. clarensis
Leaves small, 1.2–5.5 cm long; peduncles < 0.6 cm long 197. I. fuchsioides
48 Leaves large 5–12 cm long, cordate, sericeous below but not silvery; sepals completely glabrous 189. I. hypargyreia
Leaves up to 6.5 cm long, cuneate to weakly cordate, silvery; sepals pubescent near base 196. I. montecristina
49 Stamens included 50
Stamens exserted 51
50 Stem, peduncles and petioles with conspicuous squamose glands (Eastern Cuba) 187. I. balioclada
Plant lacking conspicuous squamose black glands (Western Cuba 183. I. alterniflora
51 Corolla limb deeply divided into oblong lobes (Hispaniola) 199. I. repanda
Corolla limb entire or undulate 52
52 Leaves oblong, mostly absent at anthesis; flowers in dense clusters (Cuba) 191. I. incerta
Leaves of varied shape, present at anthesis; flowers in lax cymes 53
53 Leaves wedge-shaped (St. Eustatius) 200. I. sphenophylla
Leaves usually ovate, somewhat polymorphic (Cuba, Bahamas, Florida) 198. I. microdactyla
54 Corolla hypocrateriform; stamens exserted 55
Corolla funnel-shaped or campanulate; stamens included 56
55 Sepals c. 3 mm long with a subterminal awn of similar length 321. I. hederifolia
Sepals 10–15 mm long, without a prominent subterminal awn (Jamaica) 235. I. jamaicensis
56 Trailing plants rooting at the nodes growing in wet places near the sea or in and around cultivation 57
Twining, climbing or trailing plants, not rooting at the nodes and not usually found in wet places or on sea shores 61
57 Leaves ovate, suborbicular, linear, oblong, rectangular or 5-lobed, not, or scarcely, basally cordate; seashore plants 58
Leaves lanceolate, ovate, subreniform or suborbicular but with cordate or sagittate base, plants of freshwater or dry habitats 59
58 Leaves shortly oblong, linear, lanceolate or 3–5-lobed, small, 1.5–3 × 0.8–2 cm; sepals very unequal; corolla white, 3.5–4 cm long 388. I. imperati
Leaves ovate to suborbicular, rounded or emarginate, 3.5–9 × 3–10 cm; sepals subequal; corolla pink, 4–5 cm long 339. I. pes-caprae
59 Sepals strongly mucronate, usually ciliate or pilose; plant of cultivation or waste ground I. batatas
Sepals not mucronate, glabrous; plants usually of wetland 60
60 Sepals subequal, smooth; leaves acuminate, sagittate or hastate 391. I. aquatica
Sepals very unequal, often transversely muricate; leaves rounded, obtuse or acute, never acuminate 347. I. asarifolia
61 Sepals with prominent abaxial muricate ribs; bracteoles prominent, 8–20 × 3–15 mm 62
Sepals abaxially smooth; bracteoles prominent or not 63
62 Annual herb; corolla 2.5–3.5 cm long 341. I. fimbriosepala
Perennial herb; corolla 5.5–8 cm long 342. I. setifera
63 Flowers grouped into bracteolate clusters 64
Inflorescence clearly cymose, but, if clustered, bracteoles caducous 65
64 Corolla 2–3 cm long; stigma bilobed; capsule 4-seeded 305. I. meyeri
Corolla 5–6 cm; stigma trilobed; capsule 6-seeded 234. I. indica
65 Sepals more than 10 × 10 mm in size, commonly reddish; plant a vigorous liana 352. I. philomega
Sepals < 10 mm wide, not reddish; plant herbaceous 66
66 Sepals glabrous 67
Sepals hirsute, or at least ciliate 74
67 Corolla white or cream, rarely bluish; sepals oblong or oblong-lanceolate 68
Corolla pink or blue; Sepals variable in shape 69
68 Corolla campanulate, 2.5–3 cm long; sepals oblong, nearly completely scarious, < 15 mm long 403. I. corymbosa
Corolla funnel-shaped, 5–6 cm long; sepals oblong-ovate, scarious only on the margins, often exceeding 14 mm (Jamaica) 400. I. lindenii
69 Sepals < 11 mm long, equal in length or nearly so 70
Sepals > 12 mm long or if less, very unequal in length 71
70 Sepals lanceolate, acute but not mucronate, scarious-margined; corolla blue with white tube and yellowish throat (cultivated or an escape) 257. I. tricolor
Sepals oblong or oblong-ovate, conspicuously mucronate, not scarious-margined; corolla pink, often with a dark centre 221. I. tiliacea
71 Flowers usually solitary; leaves strongly sagittate to hastate 72
Flowers usually several in cymes, very rarely solitary; leaves cordate or sagittate 73
72 Sepals lanceolate, 17–21 mm long, acuminate, subequal with prominent longitudinal veins (Netherlands Antilles) 355. I. incarnata
Sepals oblong-elliptic, rounded, < 12 mm long, unequal in size, not prominently veined 351. I. sagittata
73 Corolla bluish; peduncles short, usually < 1.5 cm; sepals narrowly ovate acute to acuminate (Jamaica) 400. I. lindenii
Corolla usually pink or pale pink; peduncles 4–12 cm; sepals obovate to suborbicular, (Hispaniola, Trinidad) 380. I. squamosa
74 Corolla white, yellow or cream, sometimes with a dark centre 75
Corolla pink, blue or purplish 77
75 Ovary and capsule pilose; corolla white 224. I. lacunosa
Ovary and capsule glabrous; corolla yellowish, sometimes with a dark centre 76
76 Corolla large, 3–4 cm long 412. I. ochracea
Corolla small, 1.5–2.5 cm long 413. I. obscura
77 Sepals obtuse, acute or acuminate but not mucronate; stigma 3-lobed; capsule 6-seeded, glabrous 78
Sepals oblong or lanceolate, distinctly mucronate; stigma 2-lobed; capsule 4-seeded, often pilose 80
78 Corolla pink (rarely white or blue); sepals oblong-lanceolate, obtuse or acute; leaves entire or 3–5-lobed 238. I. purpurea
Corolla blue with a white tube (drying pink): sepals ovate with an elongate apex, notably accrescent in fruit 79
79 Corolla < 3.5 cm long; sepals < 2 cm long at anthesis, the tips recurving; peduncle very short 237. I. hederacea
Corolla 4–4.5 cm long; sepals c. 3 cm long at anthesis, the tips erect; peduncles long or short 236. I. nil
80 Corolla < 2.5 cm long; plants annual, always slender 81
Corolla > 2.5 cm long; plants perennial or annual, usually relatively robust 82
81 Sepals oblong, 5–6 mm long 229. I. triloba
Sepals lanceolate, 10–14 mm long 225. I. leucantha
82 Slender, 1–2-flowered herb with pubescent strap-shaped sagittate leaves (Cuba, Florida, Hispaniola, Mona Island) 232. I. tenuissima
Slender or robust herbs, 1–many-flowered; leaves not strap-shaped, rarely sagittate, but, if so, completely glabrous 83
83 Sepals oblong-lanceolate; sepals chartaceous even at anthesis, unequal, the outer shorter than the inner 219. I. trifida
Sepals obovate, ovate or elliptic; sepals not chartaceous at anthesis, equal in length or nearly so 84
84 Annual herb, not rooting at nodes; cymes always lax and few-flowered, never umbellate in form 226. I. cordatotriloba
Perennial herb, often decumbent and rooting at the nodes; cymes compact, umbellate or subcapitate in form 220. I. batatas

D. Key to Hawaiian species

1 Leaves pinnate 312. I. quamoclit
Leaves simple or palmately lobed 2
2 Erect undershrub to c. 3 m; corolla pubescent 84b. I. carnea subsp. fistulosa
Trailing or twining herbs; corolla glabrous except in. I. tiliifolia 3
3 Leaves 5-lobed to or near the base 4
Leaves entire or shallowly 3-(5)-lobed 5
4 Woody liana; leaves lacking pseudo-stipules; corolla orange-red 211. I. horsfalliae
Twining herb; Leaves with cnspicuous pseudo-stipules; corolla pink 392. I. cairica
5 Corolla hypocrateriform, red, white or pale blue; stamens exserted or held at corolla mouth; twining plants 6
Corolla funnel-shaped, pink, yellowish or white, stamens included; twining or prostrate plants 8
6 Corolla red; leaves usually shallowly lobed 321. I. hederifolia
Corolla white or pale blue, usually entire 7
7 Sepals terminating in a prominent awn 5–12 mm in length; habitats with fresh water 272. I. alba
Sepals obtuse, sometimes mucronulae; saline habitats 389. I. violacea
8 Corolla yellowish, white or lilac tinged 9
Corolla pink, sometimes with a dark centre 11
9 Corolla yellowish; capsule rostrate; twining anual herb 413. I. obscura
Corolla white or lilac tinged; usually trailing perennial herbs 10
10 Creeping seashore plant, rooting at the nodes; leaves linear to oblong usually basally truncate 388. I. imperati
Prostrate or twining plant of lava flows; leaves simple or lobed but characteristically cordate at base 264. I. tuboides
11 Leaves rounded to retuse; creeping seahore species 339. I. pes-caprae
Leaves obtuse, acute or acuminate; plants of varied hábitats 12
12 Corolla pubescenrtin bud; leaves grey-tomentose when young, dotted with black glands beneath; sepals strongly accrescent and enclosing the capsule 418. I. tiliifolia
Corolla glabrous; leaves eglandular, rarely grey-tomentose, not gland-dotted beneath; sepals not strongly accrescent in fruit 13
13 Creeping freshwater aquatic herb 391. I. aquatica
Twining or prostrate herb, but if creeping, not growing in freshwater aquatic habitats 14
14 Stigma 3-lobed; sepals obtuse to acute but not mucronate 15
Stigma bilobed; sepals mucronate 16
15 Flowers clustered in a subcapitate bracteolate inflorescence; pedicels very short 234. I. indica
Flowers in lax cymes; pedicels > 10 mm long; bracteoles linear, inconspicuous 238. I. purpurea
16 Twining annual herb; corolla < 2.5 cm long 229. I. triloba
Perennial herb, usually prostrate; corolla > 2.5 cm long 17
17 Flowers in subumbellate pedunculate clusters; sepals usually ciliate; plant often pubescent; cultivated or escaped from cultivation 220. I. batatas
Flowers in 1–3-flowered cymes; sepals and leaves glabrous or nearly so; native species of seashores or near the sea 222. I. littoralis

Taxonomic account

Ipomoea L. Sp. Pl. 1: 159. 1753, nom. cons.

Acmostemon Pilg., Notizbl. Bot. Gart. Berlin-Dahlem 13: 106. 1936. (Pilger 1936: 106). Type. Acmostemon angolensis Pilg. (= Ipomoea viscoidea Choisy).

Adamboe Raf., Fl. Tellur. 4: 79. 1836 [pub. 1838]. (Rafinesque 1838a: 79). Type. Adamboe bicolor Raf. (= Ipomoea campanulata L.).

Amphione Raf., Fl. Tellur. 4: 79. 1836 [pub. 1838]. (Rafinesque 1838a: 79). Type. Amphione lobata Raf. (= Ipomoea triloba L.).

Apopleumon Raf., Fl. Tellur. 4: 72. 1836 [pub. 1838]. (Rafinesque 1838a: 72). Type. Apopleumon bignonioides (Sims) Raf. (= Ipomoea bignoniodes Sims).

Argyreia Lour., Fl. Cochinch. 1: 95, 134. 1790. (Loureiro 1790: 134). Type. Argyreia obtusifolia Lour. (= Ipomoea obtusifolia (Lour.) J.R.I. Wood & Scotland).

Argyryon St.-Lag., Ann. Soc. Bot. Lyon. 7: 120. 1880. (Saint-Lager 1880: 120). Orth. Variant of Argyreia.

Astripomoea A. Meeuse, Bothalia 6: 709. 1958. (Meeuse 1958: 709). Type. Based on Astrochlaena Hallier f.

Astrochlaena Hallier f., Bot. Jahrb. Syst. 18: 120. 1894 [pub. 1893]. (Hallier 1893b: 120), nom. illeg., non Astrochlaena Corda (1845). Type. Astrochlaena lachnosperma (Choisy) Hallier f., lectotype designated by Meeuse, Taxon 4: 199. 1955. (= Ipomoea lachnosperma Choisy).

Batatas Choisy, Mém. Soc. Phys. Genève 6: 434 [52]. 1833 [pub. 1834]. (Choisy 1834: 434). Type. Batatas edulis (Thunb.) Choisy, lectotype designated by Roberty, Boissiera 10: 147 (1964). (= Ipomoea batatas (L.) Lam.).

Blinkworthia Choisy, Mém. Soc. Phys. Genève 6: 430 [48]. 1833 [pub. 1834]. (Choisy 1834: 430). Type. Blinkworthia lycioides Choisy (= Ipomoea lycioides (Choisy) J.R.I. Wood & Scotland).

Bombycospermum J. Presl, Reliq. Haenk. 2: 137.1835. (Presl 1831–5: 137). Type. Bombycospermum mexicanum J. Presl (= Ipomoea bombycina (Choisy) Benth. & Hook f.).

Bonanox Raf., Ann. Gén. Sci. Phys. 8: 272. 1821. (Rafinesque 1821: 272). Type. Ipomoea bonanox (=Ipomoea alba L.).

Calboa Cav., Icon. 5: 51. 1799. (Cavanilles 1799: 51). Type. Calboa vitifolia Cav. (= Ipomoea neei (Spreng.) O’Donell).

Calonyction Choisy, Mém. Soc. Phys. Genève 6: 441. 1833. [pub. 1834]. (Choisy 1834: 441) Type. Based on Bonanox Raf.

Calycanthemum Klotzsch in W.C.H. Peters, Naturw. Reise Mossambique 6 (Bot. 1): 243. 1861. (Peters 1861: 243). Type. Calycanthemum leucanthemum Klotzsch (= Ipomoea leucanthemum (Klotzsch) Hallier f.).

Cleiemera Raf., Fl. Tellur. 4: 77. 1836 [pub. 1838]. (Rafinesque 1838a: 77). Type. Several syntypes cited including Cleimera hederacea (Jacq.) Raf. (= Ipomoea hederacea Jacq.).

Cleiostoma Raf., Fl. Tellur. 4: 80. 1836 [pub. 1838]. (Rafinesque 1838a: 80). Type. Cleiostoma villosum Raf. (= Ipomoea pes-tigridis L.).

Clitocyamos St.-Lag., Ann. Soc. Bot. Lyon 7: 128. 1880 (Saint-Lager 1880: 128). Type. Clitocyamos pinnatifidus Raf. (= Ipomoea quamoclit L.)

Coiladena Raf., Fl. Tellur. 2: 12 1836 [pub.1837]. (Rafinesque 1837: 12). Type. Coiladena hyemalis Raf. = Ipomoea sp. incert.

Cryptanthela Gagnep., Notul. Syst. (Paris) 14: 24. 1950. (Gagnepain 1950: 24). Type. Cryptanthela sericea Gagnep. (= Ipomoea thorelii Gagnep.)

Decaloba Raf., Fl. Tellur. 4: 76 1836 [pub. 1838]. (Rafinesque 1838a: 79). Type. Several syntypes cited, including Decaloba mutabilis (Ker-Gawl) Raf. = Ipomoea indica (Burm.) Merrill

Diatremis Raf., Ann. Gén. Sci. Phys. 8: 271. 1821. (Rafinesque 1821: 271). Type. Convolvulus nil L. (= Ipomoea nil (L.) Roth).

Dimerodiscus Gagnep., Notul. Syst. (Paris) 14: 25. 1950. (Gagnepain 1950: 25). Type. Dimerodiscus fallax Gagnep. (= Ipomoea polymorpha Roem. & Schult.).

Doxema Raf., Fl. Tellur. 4: 75. 1836 [pub. 1838]. (Rafinesque 1838a: 75). Type. Doxena sanguinea (Vahl) Raf. (= Ipomoea hederifolia L.).

Elythrostamna Bojer ex Desjardins, Rapp. Annuel Trav. Soc. Hist. Nat. île Maurice 1: 31. 1836. (Desjardins 1836: 31). Type. Elythrostamna convolvulacea Bojer ex Desjardins (= Ipomoea pileata Roxb.).

Euryloma Raf., Fl. Tellur. 4: 75. 1836 [pub. 1838]. (Rafinesque 1838a: 75). Type. Convolvulus grandiflorus L. (= Ipomoea alba L.).

Exallosis Raf., Fl. Tellur. 4: 83 1836 [pub.1838]. (Rafinesque 1838a: 83). Type. Exallosis biflora (L.) Raf. (= Ipomoea biflora (L.) Pers.).

Exocroa Raf., Fl. Tellur. 4: 80. 1836 [pub. 1838]. (Rafinesque 1838a: 80). Type. Exocroa egyptiaca Raf. (= Ipomoea cairica (L.) Sweet).

Exogonium Choisy, Mém. Soc. Phys. Genève 6: 443. 1834. (Choisy 1834: 443). Type. Exogonium bracteatum (Cav.) Choisy ex G. Don, lectotype designated by House, Bull. Torrey Bot. Club 35: 98. (1908). (= Ipomoea bracteata Cav.).

Fraxima Raf., Fl. Tellur. 4: 83. 1836 [pub. 1838]. (Rafinesque 1838a: 83). Type. Fraxima ebractea (Desr.) Raf. (= Ipomoea ebracteata (Desr.) Choisy).

Gynoisa Raf., Fl. Tellur. 4: 75 1836 [pub. 1838]. (Rafinesque 1838a: 75). Type. Gynoisia carolina (L.) Raf. (= Ipomoea cordatotriloba Dennst.).

Kolofonia Raf., Fl. Tellur. 4: 73 1836 [pub. 1838]. (Rafinesque 1838a: 73). Type. Kolofonia albivenia (Lindl.) Raf. (= Ipomoea albivenia Lindl.)

Latrienda Raf. Fl. Tellur. 4: 81. 1836 [pub. 1838]. (Rafinesque 1838a: 81). Type. Various syntypes cited including Latrienda soldanella (L.) Raf. (= Calystegia soldanella (L.) R.Br. and Latrienda imperati (Vahl) Raf. (=Ipomoea imperati (Vahl) Griseb.)

Legendrea Webb & Berth, Hist. Nat. Iles. Canar., Bot. 3, 2: 26. 1844. (Webb and Berthelot 1844–50 : 26). Type. Legendrea mollissima Webb. & Berthel. (= Ipomoea corymbosa (L.) Roem. & Schult.).

Lepistemon Blume, Bijdr. Fl. Ned. Ind. 722. 1826. (Blume 1826: 722). Type. Lepistemon flavescens Blume (= Ipomoea binectarifera (Wall.) J.R.I. Wood & Scotland).

Lepistemonopsis Dammer, Pflanzenw. Ost-Afrikas C: 331. 1895. (Engler 1895). Type. Lepistemonopsis volkensii Dammer (= Ipomoea volkensii (Dammer) J.R.I. Wood & Scotland).

Lettsomia Roxb., Fl. Ind. 2: 75. 1824. (Roxburgh 1824: 75). Type. Lettsomia cuneata (Willd.) Roxb., designated by Pfeiffer (1874: 95). (= Ipomoea cuneata (Willd.) J.R.I. Wood & Scotland).

Marcellia Choisy, Mém. Soc. Phys. Genève 10: 443. 1844. (Choisy: 1844: 443). Type. Marcellia villosa Mart. ex Choisy (= Ipomoea marcellia Meisn.).

Melascus Raf., Fl. Tellur. 4: 81 1836 [pub. 1838]. (Rafinesque 1838a: 81). Type. Melascus latifolius Raf. (= Ipomoea alba L.).

Mina Cerv. in La Llave & Lexarza, Nov. Gen. Descr. 1: 3. 1824. (La Llave and Lexarza 1824: 3). Type. Mina lobata Cerv. (= Ipomoea lobata (Cerv.) Thell.).

Modesta Raf., Fl. Tellur. 4: 76. 1836 [1838]. (Rafinesque 1838a: 76). Type. Modesta paniculata (L.) Raf. (= Ipomoea mauritiana Jacq.).

Moorcroftia Choisy, Mém. Soc. Phys. Genève 6: 431. 1833 [pub.1834]. (Choisy 1834: 431). Type. Moorcroftia pinangiana Choisy, lectotype designated by Roberty (1964: 143) = Ipomoea pinangiana (Choisy) J.R.I. Wood & Scotland.

Navipomoea Roberty, Boissiera 10: 147. 1964. . (Roberty 1964: 147). Type. Navipomoea involucrata (P. Beauv.) Roberty (= Ipomoea involucrata P. Beauv.).

Neorthosis Raf., Fl. Tellur. 4: 125 1836 [pub. 1838]. (Rafinesque 1838a: 125). Type. Not clearly cited, possibly Neorthosis coccinea (L.) Raf. (= Ipomoea coccinea L.).

Ornithosperma Raf., Fl. Ludov.: 149. 1817. (Rafinesque 1817: 149). Type. Ornithosperma serotina (DC.) Raf. (= Ipomoea orizabensis (G. Pelletan) Ledeb. ex Steud.).

Paralepistemon Lejoly & Lisowski, Bull. Jard. Bot. Belg. 56: 196. 1986. (Lejoly and Lisowski 1986: 196). Type. Paralepistemon shirensis (Oliv.) Lejoly & Lisowski (= Ipomoea shirensis Oliv.).

Pentacrostigma K. Afzel., Svensk. Bot. Tidskr. 23: 181. 1929. (Afzelius 1929: 181). Type. Pentacrostigma nyctanthum K. Afzel. (= Ipomoea longituba Hallier f.).

Pharbitis Choisy, Mém. Soc. Phys. Genève 6: 438. 1833 [pub.1834]. (Choisy 1834: 438). Type. Pharbitis hispida (Zuccagni) Choisy (= Ipomoea purpurea (L.) Roth).

Plesiagopus Raf., Fl. Tellur. 4: 78. 1836 [1838]. (Rafinesque 1838a: 78). Type. Convolvulus pes-caprae L. (= Ipomoea pes-caprae (L.) R.Br.).

Pseudipomoea Roberty, Boissiera 10: 147. 1964. (Roberty 1964: 147). Type. Pseudipomoea repens (L.) Roberty (= Ipomoea repens (L.) Lam.).

Quamoclit Mill., Gard. Dict. Abr. ed. 4(3). 1754. (Miller 1754). Type. Based on Ipomoea quamoclit L.

Quamoclita Raf., Fl. Tellur. 4: 74. 1836 [pub. 1838]. (Rafinesque 1838a: 74). Type. Various heterogeneous species cited.

Rivea Choisy, Mém. Soc. Phys. Genève 6: 407. 1833 [pub.1834]. (Choisy 1834: 407). Type. Rivea hypocrateriformis (Desr.) Choisy. Lectotype designated by Manitz (1976: 313). (= Ipomoea hypocrateriformis (Desr.) J.R.I. Wood & Scotland)

Samudra Raf., Fl. Tellur. 4: 72 1836 [pub. 1838]. (Rafinesque 1838a: 72). Type. Samudra speciosa (L.f.) Raf. (= Ipomoea nervosa (Burm. f.) J.R.I. Wood & Scotland)

Stictocardia Hallier f., Bot. Jahrb. Syst. 18: 159. 1894 [pub. 1893]. (Hallier 1893b: 159). Type. Stictocardia tiliifolia (Desr.) Hallier f. (= Ipomoea tiliifolia (Desr.) Roem. & Schult.)

Stomadena Raf., Fl. Tellur. 2: 12 1836 [pub.1837]. (Rafinesque 1837: 12). Type. Stomadena violacea Raf. (= Ipomoea sp. incert.)

Tereietra Raf., Fl. Tellur. 4: 124 1836 [pub.1838]. (Rafinesque 1838a: 124). Type. Tereietra violacea (L.) Raf. (= Ipomoea violacea L.)

Tirtalia Raf., Fl. Tellur. 4: 71. 1836 [pub. 1838]. (Rafinesque 1838a: 71). Type. Various syntypes cited.

Turbina Raf., Fl. Tellur. 4: 81. 1836 [pub. 1838]. (Rafinesque 1838a: 81). Type. Turbina corymbosa (L.) Raf. (= Ipomoea corymbosa (L.) Roth ex Roem. & Schult.).


Ipomoea pes-tigridis L.


Annual or perennial herbs, subshrubs, lianas, shrubs or small trees, very varied in habit but, most commonly, twining, less commonly decumbent or erect; vegetative parts glabrous or variously hirsute. Leaves without true stipules, alternate, usually petiolate, entire, lobed or compound with separate leaflets; pseudostipules sometimes present. Inflorescence characteristically of axillary cymes, but sometimes very dense and subcapitate or reduced to single flowers or corymbose to foliose paniculate in form, or subterminal and racemose to spicate in erect species; peduncles variable in length, rarely absent; bracts usually indistinguishable from leaves except in species with a terminal inflorescence; bracteoles very small to large, persistent or caducous, scarious, chartaceous or foliaceous, occasionally forming an involucre; pedicels short or long, rarely absent; calyx of five equal or unequal sepals, very variable in texture, coriaceous, herbaceous, scarious, persistent, often enlarging in fruit; corolla ±often showy, small or (usually) large, commonly funnelform, sometimes hypocrateriform, campanulate or suburceolate, pink or white with 5 distinct darker midpetaline bands, the limb distinct from the tube; stamens 5, usually included, equal or unequal in length, dilated and glandular-pilose at base, inserted near base of corolla tube; anthers usually narrowly oblong; pollen spheroidal, pantoporate, echinulate, the grains relatively large; disc annular, ovary 2(–5) locular, 4 (–10)-ovulate, glabrous or pubescent; style simple, filiform; stigma subglobose, 2(–3)-lobed, rarely (Astripomoea and some species in the Arborescens Clade) lobes somewhat elongate. Fruit a globose, 4 (–10) valved capsule or indehiscent; seeds (1–)4–6(–10), triquetous, ovoid or subglobose, glabrous or variously hirsute.


A mainly tropical genus, which is almost absent from temperate regions. In its widest circumscription (that is including Argyreia and Stictocardia), it is about equally common in all three tropical regions although the greatest numbers are found in the Americas. A feature of the genus is the existence of a group of around 30 species which are pantropical in distribution, many as the result of early or prehistoric dispersal. There are significant numbers of endemic species on some large islands including Cuba, Hispaniola, Madagascar and Australia but endemics on small islands or island groups are uncommon.

••• Clade A. (Species 1–233). This enormous clade includes over half the species found in the Americas. There is no obvious morphological character that unites the clade but it divides into three smaller clades. Species in the first two of these, Clade A1 (species 1–127) and Clade A2 (Species 128–215), appear always to have pollen with relatively few echinulae (Figure 9A–C) while that of Clade A3 (Species 218–232) has more numerous echinulae (Figure 10A, B). In addition, there are 3 species within clade A that lie outside Clades A1–3. These are Ipomoea setosa and I. peruviana (species 216–217) that are sister to each other and together sister to Clades A1–2. Lastly, Ipomoea cryptica (Species 233) is sister to Clade A3. Figure 1.

•• Clade A1 (Species 1–127) is very heterogenous morphologically although notable for the absence of annual species and of species with a hypocrateriform corolla and exserted stamens. It includes a number of smaller clades, which are indicated in the text, as well as the following major, principally South American, radiation, which we refer to as the Jalapa radiation after its most widespread species.

• The Jalapa radiation (Species 1–83) is centred on Paraguay, Bolivia, southern Brazil and the extreme north of Argentina. It is very poorly represented in North America. The exact boundaries of the radiation are unclear but evidence suggests that Ipomoea carnea (Species 84) and subsequent species should be excluded (Muñoz Rodríguez et al. 2019). Species in this radiation are very varied in habit but the corolla is always pubescent on the exterior. The sepals are usually ±flat, somewhat soft in texture and pubescent.

The radiation appears to be actively evolving and there are several clusters of species, which are difficult to delimit or are bridged by intermediates. To date molecular studies have not shed much light on these relationships or on species monophyly. Most species are unresolved with samples of some species, notably Ipomoea malvaeoides and I. hirsutissima appearing in several places, although in other cases samples from multiple accessions indicate monophyletic species. Results from the few species for which we have extensive sequence data confirm some species relationships suggested by morphology such as Ipomoea malvaeoides with I. paludosa, or I. argentinica with I. longibarbis but raise serious questions over others that are suggested by morphology, such as I. megapotamica with both I. hieronymi and I. opulifolia or I. nitida with I. psammophila.

Ipomoea stuckertii O’Donell, Lilloa 14: 188. 1948. (O’Donell 1948a: 188)


ARGENTINA. Córdoba, Dept. Tulumba, B. Balegno 1199 (lectotype LIL001355, designated here; isolectotype LIL).


Perennial with napiform rootstock and usually trailing, rarely twining, lanate stems, which become sparsely pilose when old. Leaves petiolate, 2.5–11 × 2.5–8 cm, deeply palmatisect with 6–9 narrowly elliptic to oblanceolate crenate acute lobes, both surfaces tomentose to thinly pilose, base cuneate; petioles 2.5–4 cm, white-pubescent. Flowers 1–3 in axillary, pedunculate cymes; peduncles 7–18 mm, pubescent; bracteoles deltoid. 2–3 mm long, caducous; pedicels 2–10 mm, pubescent; sepals subequal, 8–11 × 4–6 mm, oblong-elliptic, obtuse, white-pubescent, the inner with glabrous margins; corolla 3.5–6 cm long, funnel-shaped, pink, glabrous or with a few short hairs in bud, limb c. 2.5 cm diam. Capsules 15 × 15 mm, subglobose, rostrate; seeds 7–8 mm, long-pilose.


O’Donell (1959b: 143).


Endemic to the sub-Andean region of NW Argentina, growing on rocky mountains at around 1000 m, apparently most common in Córdoba.

ARGENTINA. Catamarca: La Paz, J. Brizuela 108 (P). Córdoba: sine data, E. Fielding (BM); camino de Carlos Paz a Pampa de Achala, 12 km antes de Copina, A.L. Pastore 367 (P, SI, US); Copina, A. Burkart 7460 (SI); San Alberto, T. Stuckert 10762 (CORD). San Luis: Ayacucho, Ruta 146 a S de Luján, R. Kiesling 4736 (SI); C. Galander s.n. [15/3/1882] (CORD). Santiago del Estero: Choya, A.T. Hunziker & A.E. Cucucci 17909 (CORD).


The palmatisect leaves, lanate stems and pubescent sepals are distinctive.

Ipomoea padillae O’Donell, Lilloa 29: 207. 1959. (O’Donell 1959b: 207)


ARGENTINA. Misiones, Dept. Candelaria, Gramajo, G.J. Schwarz 5552 (lectotype LIL001267, designated here; isolectotypes LIL, P, S, SI).


Prostrate perennial herb; stems trailing, several metres long, pilose, glabrescent. Leaves petiolate, 3–17 × 3–20 cm, 3–7-palmatilobed, the segments elliptic to obovate, narrowed towards the base, apex obtuse and mucronate, base shallowly cordate, both surfaces thinly pubescent, the lower sometimes sericeous; petioles 1–11 cm. Inflorescence of 1–8-flowered, axillary, pedunculate often compounded cymes; peduncles 2–18 cm long; bracteoles 3–5 mm long, lanceolate, caducous; secondary peduncles 1.5–5 mm; pedicels 9–30 mm long; sepals 7.5–10 × 4–6 mm, subequal, ovate, acute and mucronate, sericeous, the inner with glabrous, scarious margins; corolla 5.5–8 cm long, pink, funnel-shaped, sericeous, limb c. 4 cm diam. Capsules subglobose, 7–8 mm wide, glabrous; seeds not seen.


O’Donell (1959b: 210).


An uncommon plant of degraded cerrado in NE Argentina (Misiones) and neighbouring Rio Grande do Sul in Brazil.

ARGENTINA. Misiones: Leandro, A. Krapovikas et al. 15023 (CTES); Candelaria, Posadas-Bonpland, W.A. Archer 4611 (US); Ruta Nacional 12.2 km del peaje, M.E. Rodríguez & A. Gachez (CTES, FCQ); Apóstoles, H. Keller & Franco 4907 (CTES); Concepción, H. Keller & Franco 5732 (CTES).

BRAZIL. Rio Grande do Sul: Roque Gonzales, Rincão Vermelho, P.P.A. Ferreira & J. Durigon 590 (S); São Borja caminho para Garruchos, P.P.A. Ferreira & J. Durigon 582 (CTES).


The palmatilobed pubescent leaves and sericeous exterior of the corolla help to identify this species.

S. Heinonen et al. 117 (CTES) collected in Corrientes, Dept. Ituzaingo at Puerto Valle may represent an undescribed related species. It has trifurcate, thinly appressed pilose leaves divided to near the strongly truncate base. The leaf lobes are oblong, 3–5.5 × 0.5–1.2 cm, the flowers are solitary, borne on a 3–4 cm long, pubescent peduncle with caducous bracteoles and 5–7 mm long pedicels. The corolla is pubescent and the sepals narrowly ovate, 7–8 × 3 mm, subacute and pubescent. The leaf base is very different from that of Ipomoea padillae and other species with trifurcate leaves, such as I. delphinioides.

Ipomoea pampeana P.P.A. Ferreira & Miotto, Kew Bull. 66(2): 289. 2011. (Ferreira and Miotto 2011: 289)


BRAZIL. Rio Grande do Sul, Manoel Viana, P.P.A. Ferreira 279 (holotype ICN, isotypes K, P, SP).


Perennial twiner to 3 m, stems woody, grey-tomentose. Leaves petiolate, divided palmately to the base into five segments, 4–10 × 0.7–3 cm, narrowly elliptic to oblanceolate, acute or obtuse and mucronate, the basal lobes sometimes only lobed, noticeably larger, both surfaces grey-tomentose; petiole 2–5 cm long, grey-tomentose. Inflorescence of compound axillary cymes; peduncles 2–13 cm, tomentose; bracteoles 3–6 mm, lanceolate, caducous; secondary peduncles 1–2.5 cm; pedicels 7–10 mm, tomentose; sepals slightly unequal, outer 10–12 mm, ovate, acute, grey-tomentose, inner 11–13 mm, the margins glabrous; corolla 5–7 cm long, funnel-shaped, sericeous, pink with purple throat, limb 5–6 cm diam. Capsules 11–12 × 10 mm, subglobose, glabrous; seeds black, shortly tomentose, 7–8 mm long.


Ferreira and Miotto (2011: 291).


Grassy pampa. Endemic to the area around Manoel Viana in Rio Grande do Sul, Brazil.

BRAZIL. Rio Grande do Sul (Ferreira and Miotto 2011).


This species is probably close to Ipomoea padillae and the species represented by Heinonen et al. 117 discussed after I. padillae.

Ipomoea prolifera J.R.I. Wood & Scotland, Kew Bull. 73 (57): 1. 2018. (Wood et al. 2018: 1)


BOLIVIA. Vallegrande, on descent to Pampa Negra, J.R.I. Wood, M. Martinez & G. Aramayo 28441 (holotype USZ, isotypes LPB, OXF).


Perennial herb, clambering over shrubs or, less commonly, decumbent; stems up to c. 3 m long, pubescent with long appressed hairs. Leaves petiolate, dimorphic; upper leaves and bracts 2.5–8 × 2–10 cm, diminishing in size upwards, entire, broadly ovate-elliptic to suborbicular, rounded, base shallowly cordate to truncate, margins undulate; lower leaves 7–13 × 7–14 cm, 3–5-lobed to about halfway (rarely unequally bilobed), the lobes oblong, obtuse to acute, base shallowly cordate; both leaf forms adaxially dark green, pubescent, abaxially grey-tomentose; petioles 2.5–7.2 cm, pubescent. Inflorescence of pedunculate axillary cymes usually with 7–8 flowers, mainly near the branch tips, somewhat proliferating; peduncles (0.5) –3–4.5 cm, pubescent, often somewhat bent or twisted, diminishing in length towards apex; bracteoles caducous, not seen; secondary peduncles 0.5–2 cm; pedicels 13–20 mm, pubescent, often bent; sepals subequal, 8–9 × 5–6 mm, oblong-elliptic, densely pubescent, outer rounded with narrow scarious margins, inner with rounded or retuse with broader scarious margins; corolla 5.5–6 cm long, funnel-shaped, pale pink, pubescent, limb c. 4 cm diam.; ovary glabrous. Capsules and seeds not seen.


Figure 12.

Figure 12. 

Ipomoea prolifera A habit B adaxial surface of leaf C abaxial leaf surface D calyx E bud F sepals G corolla H corolla opened out to show stamens and style. Drawn by Eliana Calzadilla from Wood et al. 28441.


A narrow endemic restricted to seasonally very arid spiny bushland on descent to Pampa Negra in Vallegrande Province in Bolivia between 1650 and 1800 m.

BOLIVIA. Santa Cruz: Vallegrande, J.R.I. Wood et al. 28443 (LPB, OXF, USZ).


A scrambling or decumbent species with dimorphic leaves and stems which distinctly proliferate.

Ipomoea cardenasiana O’Donell, Dusenia 1: 375. 1950. (O’Donell 1950c: 375)


BRAZIL. Mato Grosso do Sul, Urucúm, M. Cárdenas 4448 (holotype LIL001235).


Vigorous twining perennial to 3 m; stems stout, glabrous. Leaves petiolate, 4–10 × 3–8 cm, mostly 3-lobed to half way with acute lobes but some leaves ovate with one or two marginal teeth, base broadly cordate, apex shortly acuminate and mucronate, adaxially glabrous apart from veins pubescent near base, abaxially paler, pubescent especially on the veins; petioles 2–5 cm. Inflorescence of pedunculate, axillary cymes; peduncles 2–5 cm, stout, glabrous; bracteoles c. 5 mm long, oblong, muconate, papery, caducous; secondary and tertiary peduncles 0.8–1.5 cm; pedicels 5–10 mm, pubescent; sepals slightly unequal, outer 15–20 × 10–12 mm, ovate, narrowed to an obtuse apex, minutely puberulent, pale green; inner sepals 18–22 × 12 mm, elliptic, acuminate to an obtuse apex, sericeous, palid; corolla 7–9 cm long, funnel-shaped, pale pink, pubescent in bud, limb 5 cm diam., shallowly lobed. Capsules ovoid, 15 × 10 mm, glabrous, brown, enclosed by sepals; seeds 11 × 6 mm (possibly immature), brown, pilose with very long marginal hairs.


Wood et al. (2015: 53, photo).


A narrow endemic restricted to the Bolivia-Brazil border around Corumbá and Puerto Suárez at the edge of the Pantanal where it is locally common on scrubby roadsides around 100–150 m.

BRAZIL. Mato Grosso do Sul: Corumbá, Dorrien Smith 80 (K); Estrada da Codrasa, Ladãrio, Bartolotto et al. 8 (MBM).

BOLIVIA. Santa Cruz: Germán Busch, Puerto Suárez area, J.R.I. Wood & D. Villarroel 25902 (K, LPB, UB, USZ); J.R.I. Wood et al. 27885 (K, LPB, USZ).


A very distinctive species because of its large corolla, acutely 3-lobed leaves and large pale green sepals.

Ipomoea aemilii (O’Donell) J.R.I. Wood & R. Degen, Kew Bull. 71, 25: 3. 2016. (Wood et al. 2016b: 3)

Ipomoea malpighipila var. aemilii O’Donell, Arq. Mus. Paranaense 9: 228. 1952. (O’Donell 1952: 228). Type. PARAGUAY. Alto Paraná, 1909/10, K. Fiebrig 5684 (holotype SI001300, isotypes G? n.v., GH, LIL, SI, US).

Ipomoea aurita Hassl., nom. nud., Add. Plantae Hasslerianae 18. 1917. (Hassler 1917: 18).


Based on Ipomoea malpighipila var. aemilii O’Donell


Perennial of a pale green colour from a woody xylopodium; stems erect to 1 m high, apparently unbranched, densely hirsute with somewhat rough mostly appressed hairs. Leaves sessile, 16–27 × 0.4–0.8 cm, narrowly oblong, slightly narrowed to a cuneate base, apex obtuse and mucronate, coarsely tomentose on both surfaces, abaxially prominently 3–5-veined. Inflorescence terminal, rather short and dense < 7 cm long, formed of (1–)3-flowered cymes in the axils of leaf bracts; bracts 2–6.5 cm long, diminishing in size upwards, apparently deciduous and absent from uppermost cymes; peduncles 2–4 mm, relatively stout, densely hirsute; bracteoles c. 3 × 0.5 mm, lanceolate, acuminate, almost hidden by the indumentum; pedicels 5–7 mm, densely hirsute; sepals 7–8 × 4–5 mm, broadly elliptic, densely hirsute, slightly unequal, outer obtuse, inner rounded to retuse with glabrous, scarious margins; corolla 4–5 cm long, pink, funnel-shaped, densely pubescent on mid-petaline bands, limb 2.5–3 cm diam. Capsules glabrous; seeds not seen.


Figure 13.

Figure 13. 

Ipomoea aemilii. A habit B stem base C leaf surface D leaf apex E flower bud F outer sepal G inner sepal. Drawn by Rosemary Wise A from Itapú Binacional 1046; B–G from Fiebrig 5684.


Endemic to Paraguay. In sabanas in the area north of Hernandarias, especially in the Reserva Tatí Yupí.

PARAGUAY. Alto Paraná: Reserva Tatí Yupí, Itaipú Binacional 1046 (MO); G. Caballero Mamori 1423 (CTES); Com. Puerto Palma, C. Romero Pereira 14 (SCP); Pirá Pytá, A. Schinini et al. 18152 (CTES).


Distinguished from Ipomoea malpighipila by the simple leaves and distinct indumentum.

Ipomoea malpighipila O’Donell, Lilloa 23: 448. 1950. (O’Donell 1950a: 448)


ARGENTINA. Misiones, Dept. San Ignacio, Gob. Roca, 22 Nov. 1947, G.J. Schwarz 2338 (holotype LIL001259).


Erect perennial herb or subshrub from a xylopodium, stems 0.5–1 m long, usually simple, distinctly angled, adpressed pubescent with t-shaped hairs. Leaves shortly petiolate, 3-fid from near base, lobes 7.5–15 × 0.2–1.2 cm, narrowly oblong, shortly mucronate, base attenuate, both surfaces adpressed-pubescent, abaxially prominently veined; petioles 1–1.5 cm. Inflorescence elongate (to 10 cm), terminal, formed of shortly pedunculate cymes from the axils of leaf-like bracts, these absent in the upper part of inflorescence; peduncles 0.4–1.5 cm, adpressed pubescent; bracteoles ovate, caducous; pedicels 3–8 cm, adpressed pubescent; sepals equal, 6–8 × 4–6 mm, elliptic to suborbicular, obtuse and often mucronate, subsericeous; corolla 3.5–5 cm long, pink, funnel-shaped, adpressed pubescent. Capsules 7–10 × 7–8 mm, subglobose, glabrous; seeds 6 × 4 mm, blackish-brown, margins lanate.


O’Donell (1959b: 177).


Almost endemic to the province of Misiones in Argentina where it grows in seasonally flooded grassy pampa. There appear to be no recent records from Paraguay or Brazil.

ARGENTINA. Misiones: San Ignacio, D. Giambaggio s.n. (SI); G.J. Schwarz 5334 (E, LIL, S); M.E. Rodríguez & A. Gochez 1179 (MA); H. Keller et al. 6464 (CTES); J.E. Montes 458 (LIL, S).

PARAGUAY. Itapúa: Encarnación, T. Rojas 29 (SCP).

BRAZIL. Rio Grande do Sul: Agusto s.n. (ICN18804), fide Ferreira and Miotto (2009: 446).


The T-shaped hairs are difficult to observe but are distinctive. Ipomoea malpighipila is usually easily identified by the terminal inflorescence and obscurely pubescent, trifid leaves with narrowly oblong lobes.

Ipomoea cordillerae J.R.I. Wood & Scotland, Kew Bull. 72 (9): 9. 2017. (Wood and Scotland 2017a: 11)

Ipomoea malveoides Meisn. var. ovata Hallier f., Bull. Herb. Boiss. 7(5): append. 1: 152. 1899. (Hallier 1899b: 52). Type. PARAGUAY. [Cordillera], Cordillera de Peribebuey, 6 April 1883, B. Balansa 4391 (lectotype G00174792, designated by Wood and Scotland (2017a: 11), isolectotypes G, P).


Based on Ipomoea malveoides Meisn. var. ovata Hallier f.


Erect subshrub to at least 50 cm; stems woody below, ± glabrescent; above herbaceous, softly white-tomentose. Leaves very shortly petiolate, 2.4–7 × 3.2–5 cm, ovate, oblong or oblong-elliptic, acute and mucronate, base broadly cuneate, margin entire, both surfaces softly pubescent, abaxially more densely so, paler, adaxially somewhat glabrescent on very old leaves; petioles 0–4 mm, densely pubescent to villous. Inflorescence usually of solitary, pedunculate axillary flowers forming a long terminal raceme; occasionally of axillary cymes with up to five flowers from the uppermost leaf axils; bracts leaf-like except the uppermost of which are much reduced; peduncles 0.8–4 cm, densely white-pubescent; bracteoles 6 mm long, linear filiform; pedicels 0.6–7 cm, densely pubescent; sepals with a dark gland near base, somewhat unequal, outer 9–15 × 2–4 mm, narrowly to broadly ovate, acuminate or acute and mucronate, tomentose, inner similar bur with broad scarious margins; corolla 6–6.5 cm long, funnel-shaped, pink, pubescent, limb c. 5 cm diam. Capsules c. 1.2 × 0.8 cm, ovoid, glabrous; seeds 7 × 4 mm, blackish, glabrous.


Figure 14.

Figure 14. 

Ipomoea cordillerae. A habit (flowering plant) B adaxial leaf surface C abaxial leaf surface D habit (fruiting plant) E portion of stem and leaves F outer sepal G inner sepal H seed J form with branched inflorescence. Drawn by Rosemary Wise A–C from Hassler 8714 (GH); D–H from Balansa 4391: J from Hassler 485. Drawn by Rosemary Wise.


Endemic to Paraguay and growing in forest clearings (fide Balansa 4391). PARAGUAY. Cordillera: E. Hassler 285 (K, P), 1903 (K, P), 8714 p.p. (BM, K).


Characterised by the relatively long acuminate or acute and mucronate sepals usually around 12 mm in length combined with the softly tomentose indumentum and ovate-elliptic leaves. In the type the leaves are silvery beneath but this is less obvious in the other cited collections. Ipomoea paraguariensis differs in the much shorter silvery sepals and more strictly terminal inflorescence and I. estrellensis differs in the shorter, obtuse to subacute sepals, the shorter peduncles and the ciliolate leaf margins. We have seen no modern collections of this species.

Specimens of Hassler 8714 are mixed, those at BM and K are this species but some specimens with this number are Ipomoea paraguariensis. They are all labelled as from Villarrica where Ipomoea paraguariensis grows but the specimens of I. cordillerae presumably came from the Pirebebuy area.

• Speces 9–18 form a complex in which Ipomoea malvaeoides is the best-known and most common species.

Ipomoea paludosa O’Donell, Lilloa 23: 495. 1950. (O’Donell 1950b: 495)

Ipomoea malvaeoides var. integrifolia Chodat & Hassl., Bull. Herb. Boiss. Ser. 2, 5: 690. 1905. (Chodat and Hassler 1905: 690). Type. PARAGUAY. Canindeyú, Río Jezuí Guazú, E. Hassler 5734 (lectotype G00175132, designated here; isolectotypes BM, G, GH, K, MPU, P).

Ipomoea malvaeoides forma apiculata Chodat & Hassl. [as var. uliginosa forma apiculata ], Bull. Herb. Boiss., ser. 2, 5: 691. 1905. (Chodat and Hassler 1905: 691). Type. PARAGUAY. Cordillera, Tobatí, E. Hassler 6274 (?G, n.v.).

Ipomoea malvaeoides var. uliginosa Chodat & Hassl., Bull. Herb. Boiss. Ser. 2, 5: 691. 1905. (Chodat and Hassler 1905: 691). Type. PARAGUAY. Cordillera, Tobatí, E. Hassler 6405 (lectotype G, n.v., designated by O’Donell (1953a: 373), isolectotype BM000089442).

Ipomoea paludosa var. uliginosa (Chodat & Hassl.) O’Donell, Lilloa 26: 373. 1953. (O’Donell 1953a: 373). Type. Based on Ipomoea malvaeoides var. uliginosa Chodat & Hassl.


ARGENTINA. Misiones, Dept. San Ignacio, Gob. Roca, G. J. Schwarz 5283 (lectotype LIL001271, designated here; isolectotypes CTES, LIL).


Erect undershrub 0.5–1.5 m from a woody rhizome, stems glabrous or with a few scattered hairs, sparingly branched, often simple. Leaves shortly petiolate, 2.5–11 × 0.6–2.2 cm, oblanceolate, acute or rounded and strongly apiculate, cuneate at base, adaxially glabrous to thinly adpressed pilose, abaxially adpressed pilose, veins prominent on both surfaces, esp. abaxially; petioles 0.5–1 cm long, thinly pubescent. Inflorescence long, terminal, raceme-like, formed of mostly2–3-flowered cymes, commonly reduced to single flowers; bracts leaf-like but diminishing in size upwards; peduncles 0.2–3 cm long; bracteoles 3–4 mm, lanceolate, caducous; pedicels 2–10 mm, pubescent; sepals 5–8 mm, ovate, acute to obtuse and apiculate, sericeous to pubescent, inner sepals similar but obtuse and with glabrous, scarious margins; corolla 3.5–5.5 cm long, pink, funnel-shaped, sericeous on midpetaline bands, limb 2–2.5 cm diam., undulate. Capsules c. 8 × 6 mm, ovoid, glabrous; seeds long-pilose.


O’Donell (1959b: 213); Figure 15C.

Figure 15. 

Photographs of Ipomoea species. A–B I. setosa subsp. pavonii A fruit B flower C I. paludosa, subspicate inflorescence D I. lilloana, storage root E I. opulifolia, storage root, leaves and flower. A, B, D, E Maira Martinez; C Hector Keller.


Flooded plain in the Paraná basin in Argentina, Brazil and Paraguay. ARGENTINA. Misiones: San Ignacio, F.O. Zuloaga & M. Kostlin 9948 (SI); Candelaria, H. Keller & Paredes 10563 (CTES); Bonpland, E.L. Ekman 1432 (K, S); Capital, T.M. Pedersen 13661 (C, CTES).

PARAGUAY. Alto Paraná: Est. Río Bonito, E. Zardini & Vieira 41978 (FTG, PY). Amambay: Est. Carmen de la Sierra, N. Soria 4725 (CTES, FCQ). Caaguazú: Coronel Oviedo, A. Krapovickas et al. 13848 (CTES). Caazapá: Enramadita, I. Basualdo 001902 (FCQ, MO, FTG). Canindeyú: Reserva Mbaracuyú, B. Jiménez & G. Marín 1962 (BM, MA). Central: A. Schinini 5717 (CTES). Concepción: Est. Ybyraty, F. Mereles 8580 (CTES, FCQ). Cordillera: Peribebuy, B. Balansa 4392 (P); Tobatí, R.O. Vanni et al. 185 (CTES, PY). Guairá: Cordillera de Ybyturuzú, F. Mereles 3724 (FCQ). Itapúa: Yacyreta Island Reserve, E. Zardini & Gamarra 55715 (ARIZ); Trinidad, M. Ortiz 850 (FCQ). Paraguarí: 3 km antes de Caballero, Calviño et al. 3774 (FCQ). San Pedro: Est. San Antonio, N. Soria 5363 (CTES, FCQ).

BRAZIL. Mato Grosso do Sul: Faz. Campo Alto, Corumbá, A. Pott et al. 5576 (CPAP, CTES); Hatschbach et al. 76514 (MBM).


Plants from Argentina are relatively uniform but in Paraguay they are more variable, the leaves sometimes strongly apiculate and/or the inflorescence rather lax and few-flowered.

Ipomoea morongii Britton in Morong, T. & Britton, N.L., Ann. New York Acad. Sc. 7: 171. 1892. (Morong and Britton 1892: 171)

Ipomoea malvaeoides var. trifida Hallier f., Bull. Herb. Boiss. 7 (5), append. 1: 52. 1899. (Hallier 1899b: 52). Type. PARAGUAY. Cordillera de los Altos, E. Hassler 1938 (lectotype G00174972, designated here).

Ipomoea malvaeoides var. heterophylla Hallier f., Bull. Herb. Boiss. 7 (5), append. 1: 52. 1899. (Hallier 1899b: 52). Type. PARAGUAY. [Cordillera], San Bernardino, E. Hassler 1796 (lectotype G00174971, designated here).

Ipomoea malvaeoides forma intermedia Chodat & Hassl. [as var. heterophylla forma intermedia ], Bull. Herb. Boiss., ser. 2, 5: 690. 1905. (Chodat and Hassler 1905b: 690). Type. PARAGUAY. Cordillera de Los Altos, E. Hassler 3456 (lectotype G00174963, designated here; isolectotypes G).


PARAGUAY. [Central], Luque, T. Morong 303 (holotype NY00319204, isotypes GH, MO, PH, US, WIS).


Erect undershrub to 1.2 m, stems below woody, glabrous, reddish above herbaceous, densely puberulent. Leaves petiolate, lower leaves 9–10 × 2–4 cm, entire, ovate obtuse to acute and mucronate, base cuneate, upper leaves (2–)3-lobed with the laterals much shorter than the central lobe which is usually lanceolate, acuminate, the uppermost leaves noticeably smaller and with narrower lobes, both surfaces finely tomentellous, abaxially paler; petioles1–2.5 cm, puberulent. Inflorescence of shortly pedunculate cymes from the upper leaf axils; peduncles 2–4 (–9) cm, puberulent; bracteoles 3–4 × 1 mm, oblong-lanceolate, caducous; secondary peduncles 0.7–1.8 cm; pedicels 6–10 mm, puberulent; sepals subequal, tomentellous, outer 7–9 × 5–6 mm, ovate, acute to obtuse, inner similar but with scarious, less hirsute margins; corolla 4.5–6.5 cm long, pink, pubescent, funnel-shaped; limb 3–5 cm diam., entire. Capsules and seeds not seen.


Figures 16, 17B.

Figure 16. 

A–D Ipomoea malvaeoides. A habit B abaxial leaf surface C seed D leaves (var. lineariloba). E–J Ipomoea morongii. E habit F outer sepal G inner sepal H corolla opened out to show stamens J ovary and style. Drawn by Rosemary Wise A, B from Krapovickas et al. 412477; C from Schinini 30429; D from St. Hilaire 2703, E–J from Hassler 3307.

Figure 17. 

Photographs of Ipomoea species. A I. haenkeana B I. morongii C I. malvaeoides D I. hieronymi. A John Wood; B, C Tom Carruthers; D Keith Ferguson.


Endemic to the area around Lago Ypacaraí in Central and Cordillera departments in eastern Paraguay.

PARAGUAY. Central: Ypacaraí, E. Hassler in Rojas 11473 (BM, K, NY). Cordillera: Emboscada, I. Basualdo 1021 (CTES, FCQ); Emboscada hacia Nueva Colombia, R. Degen 1385 (CTES, FCQ); Nueva Colombia, J.R.I. Wood et al. 28147 (FCQ); costa del Lago Ypacaraí, C. Quarin et al. 1488 (CTES); San Bernardino, E. Hassler 3307 (P), T. Rojas 1694 (LIL, SI), T. Rojas 14136 (SCP).


Ipomoea morongii is heterophyllous on the same plant with some leaves entire and some trifurcate. In lectotypifying the synonyms of Ipomoea morongii, we have endeavoured to choose specimens which show heterophylly and at least some trifurcate leaves. G00174972 is the only specimen at G annotated trifida by Hallier, although he also, confusingly, annotated it as I. heterophylla. The portion in the envelope which is clearly trifid should be treated as the lectotype in the event of any dispute. The specimen G00174971 of Hassler 1796 is designated as the lectotype of Ipomoea malvaeoides var. heterophylla because it has some trifurcate leaves even though it was not annotated by Hallier.


Although this species is clearly closely related to I. malvaeoides and could possibly be treated as a variety of it, it is usually easily distinguished by the trifurcate tomentose stem leaves with broad segments conspicuously fused in their lower half. The type is less hairy than most specimens.