A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae)

Abstract The Morelloid clade, also known as the black nightshades or “Maurella” (Morella), is one of the 10 major clades within Solanum L. The pantropical clade consists of 75 currently recognised non-spiny herbaceous and suffrutescent species with simple or branched hairs with or without glandular tips, with a centre of distribution in the tropical Andes. A secondary centre of diversity is found in Africa, where a set of mainly polyploid taxa occur. A yet smaller set of species is found in Australasia and Europe, including Solanum nigrum L., the type of the genus Solanum. Due to the large number of published synonyms, combined with complex morphological variation, our understanding of species limits and diversity in the Morelloid clade has remained poor despite detailed morphological studies carried out in conjunction with breeding experiments. Here we provide the first taxonomic overview since the 19th century of the entire group in the Old World, including Africa, Asia, Australia, Europe and islands of the Pacific. Complete synonymy, morphological descriptions, distribution maps and common names and uses are provided for all 19 species occurring outside the Americas (i.e. Africa, Asia, Australia, Europe and islands of the Pacific). We treat 12 species native to the Old World, as well as 7 taxa that are putatively introduced and/or invasive in the region. The current knowledge of the origin of the polyploid species is summarised. A key to all of the species occurring in the Old World is provided, together with line drawings and colour figures to aid identification both in herbaria and in the field. Preliminary conservation assessments are provided for all species.

) C Strongly ridged and often purple coloured stems present in many species (S. tarderemotum, NIJ 2010-5) D Glandular hairs present in some species of the Morelloid clade (S. memphiticum, A34750473) E Typical stellate, white flowers with spreading or reflexed corolla lobes (S. tarderemotum, A14750151) F Fleshy round berries that are black, green, yellow, orange or red depending on the species (S. nigrum, A44750150) G Stone cells (also known as sclerotic granules or brachysclerids) are found in the fruits of most species of the Morelloid clade and are round in shape as compared to the tear-drop shaped or ellipsoid seeds (S. umalilaense, A24750133) H Stone cells are often easy to see in herbarium specimens (e.g. S. sarrachoides, Blom s.n. BM001207745). Photos by S. Knapp and G. van der Weerden.  Solanum villosum Mill. 24 (2n=4x=48) nigrum, S. scabrum and S. villosum, while five species currently established in the Old World are widespread weeds originally native to South America but have been taken in the reverse direction, often as contaminants of wool; S. chenopodioides, S. nitidibaccatum, S. pygmaeum, S. sarrachoides and S. triflorum (Tables 2-6; Särkinen et al. 2015a). An overview of the entire section in the Old World, including a revision of the nomenclature and typification of the more than 370 names associated with these taxa, has never been done but is needed in order to provide identification tools for these difficult and morphologically very similar species. Here we provide a taxonomic revision of all 19 species of the Morelloid clade (black nightshades) occurring in the Old World based on a detailed morphological study; we include native and introduced taxa. This is part of our molecular systematic and taxonomic work focusing on producing a monographic treatment of the entire Morelloid clade which has to date focused on understanding species diversity and delimitation in the New World (e.g. Barboza et al. 2013;Särkinen et al. 2013Särkinen et al. , 2015a.

History, taxonomy and relationships of the Morelloid clade
The European species of black nightshades were known to the ancient Greeks and Romans, who used them medicinally. In the 1 st century AD, Pliny the Elder (Riley 1855) called the plant "cucubalus, strumus or strychnon" [translated from the Greek] and documented its use against stings, wounds and lumbago. Dioscorides, whose De (Dillenius 1732). He recognised the European S. nigrum (as var. vulgare), S. villosum (as S. nigrum var. villosum), S. americanum (as S. nigrum var. patulum) and included the African cultivated species S. scabrum (as S. nigrum var. guineenense); but he had not seen material of other species treated here (see individual species treatments for details). He clearly recognised all these taxa as very similar and as variants of a worldwide species; his diagnosis reads "Habitat in Orbis totius, cultis" [Habitat in all the world, cultivated]. He also noted many of these looked like mixtures ("Tot varietates β, γ, δ, ε, ζ videntur esse hybridae proles"). In the Species plantarum (Linnaeus 1753), he did not cite many of the works based on non-European plants (e.g. Piso 1648; Rheede von Draakestein 1689), which he had previously cited in Hortus cliffortianus (Linnaeus 1737) and, in the Clifford herbarium (BM), only specimens of S. nigrum, S. scabrum and S. villosum are preserved.
In the sixth edition of his Gardener's dictionary, Philip Miller used Linnaean binomials for the first time (see Stearn 1974). In this work, he (Miller 1768) described seven members of the Morelloid clade, five of these as new names (S. villosum Mill., S. luteum Mill., S. rubrum Mill., S. americanum Mill., S. scabrum Mill.). He did not recognise infraspecific taxa, but also did not indicate he was raising Linnaeus's varieties to species level.
Lamarck (1794) recognised seven taxa, including some not known to either Miller or Linnaeus, such as S. radicans L.f. and S. corymbosum Jacq. (members of the clade belonging to the Radicans group, see Särkinen et al. 2015a). He additionally described S. chenopodioides Lam., from material said to be from "île de France" (Mauritius, but see species description) and S. triangulare Lam. based in part on an illustration from Rumphius (1750, = S. scabrum). Some of these early authors re-used epithets (e.g. villosum used by both Miller and Lamarck), but it is not clear whether they were referring to earlier names or not; the principle of priority had not yet become established for botanical naming (see Knapp et al. 2004).
The name for the Morelloid clade is derived from Dunal's (1813: 119) un-ranked group "Maurella" that included herbaceous or subherbaceous species with entire leaves. He included 15 species, all of which are still considered members of the clade. In his Solanorum synopsis (Dunal 1816), he maintained this group, adding to it taxa described by himself and others, most of which (with the exception of S. quadrangulare Thunb. = S. africanum Mill., a member of the Dulcamaroid clade, see Knapp 2013) are still considered related. Dumortier (1827) used this group for his conspectus of the Belgian species, but with Dunal's spelling changed to "Morella". In general, the concept of Morella was narrow and included only those species later recognised as members of Solanum sect. Solanum, but did not include species now recognised as part of the more broadly defined group (Bohs 2005;Weese and Bohs 2007;Särkinen et al. 2013Särkinen et al. , 2015a. In the Prodromus, Dunal (1852) paid little attention to earlier names and erected an entirely new framework for Solanum mostly composed of gradi ambigui (names of ambiguous rank). Morella, however, was one of the names he continued to use. Within it, Dunal (1852) recognised two groups based on the inflorescence position, "Morellae spuriae" (six spp.) and "Morellae verae" (54 spp.). Circumscription of "Morella" remained obscure and loose during most of the 19 th and 20 th centuries, with many herbaceous non-spiny taxa treated as members of the group, resulting in many names associated with the Morelloid clade. Many of these names do not belong to the clade as now recognised based on phylogenetic data (Bohs 2005;Weese and Bohs 2007). An extreme example of this is S. stipuloideum Rusby from the morphologically distinct Potato clade (Spooner and Knapp 2013), which was assigned to Solanum sect. Solanum in the original description (Rusby 1907).
The very numerous treatments of these species in European floristic works (see species descriptions) usually did not specifically treat these taxa as belonging to infrageneric groups. Often these species were the only solanums treated in these floristic works, and they were often called "black nightshades" (e.g. Opiz 1843). Von Wettstein (1895) followed Dunal's scheme in his treatment of the European species, as did Dammer (1906) and Bitter (1917Bitter ( , 1919 for Africa and Asia. Bitter (1917) was the first to explicitly recognise the group at the sectional level. Following the rules on use of autonyms, Seithe (1962) was the first to re-name the group containing the type species of the genus (S. nigrum) Solanum section Solanum; she also recognised sects. Campanulisolanum Bitter, Chamaesarachidium Bitter and Episarcophyllum Bitter (all groups confined to the New World, see Barboza 2003; Barboza and Hunziker 2005), now considered part of the larger Morelloid clade (Särkinen et al. 2015a). Her sectional names were followed by Danert (1967Danert ( , 1970 with little change. D'Arcy (1972) lectotypified the infrageneric groupings in Solanum and provides an overview of the history of these infrageneric names.
Within the Morelloids, four well-supported clades have been recognised based on a detailed molecular phylogenetic study (Särkinen et al. 2015a). Prior to the use of molecular characters in phylogenetic analysis (e.g. Bohs 2005;Weese and Bohs 2007), the Morelloid clade thus defined was not recognised as a natural group. These clades loosely correspond to the previously recognised morphological sections: (1) the Radicans clade which comprises four of the species (but does not include the type species, S. triflorum Nutt.) of Solanum sect. Parasolanum A.Child (Bohs 2005); (2) the Episarcophyllum clade that includes most species of Solanum section Episarcophyllum Bitter; (3) the Chamaesarachidium clade that includes two species of Solanum section Chamaesarachidium Bitter; and finally the largest group (4) the Black nightshade clade, that includes all species of the traditional Solanum sect. Solanum. The first three clades are restricted to the New World, while most species of the Black nightshade clade occur in the New World but with a secondary centre of diversity in the Old World that is treated in this monograph.
The number of taxa included in this clade has not been clear, in part because it contains many widespread and morphologically variable species and has always been considered difficult. Although Edmonds (1972) suggested estimates of species richness had been exaggerated in the group and provided relatively low estimates of species numbers, our ongoing work in the group shows the clade includes ca. 75 species that are mostly restricted to South America (Särkinen et al. 2015a). Nineteen black nightshade species are found in the Old World, of which twelve are native there (four narrowly endemic) and not found in the Americas (Table 2; Särkinen et al. 2015a); the other seven are introductions from the New World.
Numerical taxonomic studies have been undertaken in order to resolve species relationships, parental origin of polyploids and species delimitation in these species (Soria and Heiser 1961;Heiser et al. 1965;Edmonds 1978), but the power of these methods has remained limited due to the complex and often overlapping morphological variation between the closely related species. Species of black nightshades show large amounts of morphological variation, especially in growth form, leaf morphology and indumentum.
Modern regional taxonomic treatments of the Old World members of the Morelloid clade have been done for Europe (Hawkes and Edmonds 1972), India (Ganapathi andRao 1986a, 1988;Schilling and Andersen 1990), Africa and Madagascar (Bitter 1912a(Bitter , 1912b(Bitter , 1913a(Bitter , 1921(Bitter , 1923Jaeger 1985;Bukenya and Hall 1988;Bukenya 1993;Bukenya and Carasco 1995;Edmonds and Chweya 1997) and Australia (Henderson 1974). Edmonds and Chweya (1997) remains the most thorough account of the black nightshades in the Old World, but includes only some of the species known to occur in Africa and does not treat species from Asia or those known from Australasia and the Pacific. Regional floristic treatments for regions of Africa have recently been published with detailed descriptions of local morphological variation (Edmonds 2005(Edmonds , 2006a(Edmonds , b, 2012. Schilling and Andersen (1990) clarified some of the nomenclatural problems and issues relating to misapplication of names in the Indian subcontinent in relation to the most commonly occurring species in the region.
The Old World species of the Morelloid clade do not form a monophyletic group. Phylogenetic analysis using plastid DNA sequence data (Särkinen et al. 2015a;T. Särkinen et al. in prep.) indicates that the native Old World polyploid species (S. hirtulum, S. memphiticum, S. nigrum, S. opacum, S. retroflexum, S. scabrum, S. tarderemotum, S. villosum, S. umalilaense) form a distinct group, to which S. alpinum does not belong. Polyploids from Africa are not each other's closest relatives. Other species occurring in the Old World are members of distinct South American clades.

Habit and stems
Members of the Morelloid clade are either herbs or shrubs; species occurring in the Old World range from annual (e.g. S. triflorum) to short-lived perennials (e.g. S. retroflexum, S. tarderemotum) and most are herbaceous, although some species can develop woody bases and appear to be somewhat shrubby (e.g. S. villosum). Stems are usually weak and occasionally somewhat scrambling, but can reach 2+ m in height. Plants of all species usually have herbaceous upper stems, even if the base is woody. The stems can be hollow (drying flattened, e.g. S. tarderemotum) or solid (e.g. S. americanum, S. villosum); this can be a useful character for identification of herbarium specimens.
Sympodial growth is characteristic of Solanaceae, giving the stems a typical "zigzag" appearance; details of sympodial structure have proved useful for infrageneric classification within Solanum (Child and Lester 1991;Knapp 2002a). Vegetative growth is initially monopodial, but with the onset of flowering becomes sympodial. The inflorescence is developmentally terminal and stem continuation is initiated in the axil of the leaf below each inflorescence. Each lateral shoot with alternate leaves arranged in a 1/3 phyllotaxic spiral and a terminal inflorescence is termed a sympodial unit. In some cases, when the axes of sympodial units are fused, the inflorescences appear to originate laterally from the middle of an internode; when growth of the axes is suppressed, the leaves appear paired (geminate) at a node (Danert 1958). All of the members of the Morelloid clade have difoliate sympodial units with leaves sometimes strongly paired (geminate) at the nodes and the inflorescences often arise internodally through axis fusion (Danert 1958(Danert , 1967. Occasionally inflorescences appear to be opposite the geminate leaves (e.g. S. hirtulum) especially on very young shoots (e.g. S. americanum).
"Spinose" processes are common on herbaceous stems in many species of black nightshades. They usually occur along the angles of upper parts of larger stems and are often decurrent from leaf bases. These are not true prickles, like those found in the "spiny" solanums (Leptostemonum clade, see Knapp and Vorontsova 2016) but are similar in that they are outgrowths of the epidermis and are usually associated with trichomes as the enlarged basal portions of stem trichomes that have fallen off. They have been used to differentiate species in this group, but these structures are variable within species where they do occur and even within stems on a single plant. In addition, they often change markedly in appearance when plants are pressed and dried. Their absence, however, can be diagnostic when combined with other characters.

Leaves
Species of the Morelloid clade have simple leaves that are generally elliptic or ovate in outline. Solanum retroflexum has a distinctive rhomboid leaf shape and S. scabrum leaves are usually broadly ovoid with long petioles. As with other vegetative characters in this group, leaf morphology can be extremely variable within a species or even in a single plant. Many of the infraspecific names in S. nigrum are based on variation in leaf morphology, particularly with respect to lobing of the margins.
Leaf margins vary from entire to quite deeply sinuate and lobed. Most populations of S. triflorum have deeply pinnatifid leaves, but a wing of leaf blade is always present along the midrib. Other species have variously entire or toothed margins and often the teeth occur only in the basal half to third of the leaf blade. The leaf blades are usually somewhat decurrent on to the petiole and the leaf base is cuneate to attenuate. Leaf apices are acute to attenuate, but vary considerably within species.
Petiole length to some extent is related to leaf size and, on individual plants, larger leaves always have longer petioles. As Solanum scabrum tends to have long petioles with little decurrent leaf blade tissue, this character can be helpful in distinguishing it from S. nigrum or from the sympatric S. tarderemotum.

Pubescence
Trichomes in species of the Morelloid clade are simple or branched (e.g. S. pallidum Rusby of the Andes), but never stellate (Seithe 1962;Roe 1971). Old World species have only simple trichomes, these being usually 1-6-celled and uniseriate. Occasionally the trichome base is enlarged with the lowermost cell much larger than more distal cells and these enlarged bases persist as "pseudospines" on stems (see above). Much importance has been placed on differences in density of pubescence as a taxonomic character (e.g. in Europe the densely pubescent plants of S. nigrum sometimes recognised infraspecifically as var. or subsp. schultesii in European floras), but pubescence within taxa is continuously variable and apparently also related to environment, with plants growing in sunny sites more densely pubescent.
The presence or absence of glandular trichomes has also been previously treated as taxonomically significant (see Edmonds 1977Edmonds , 1979b, with glandular and eglandular morphotypes of the European species S. nigrum and S. villosum being treated as separate subspecies or varieties (see Edmonds 2012). Manoko (2007;Manoko et al. 2008) showed that this character did not correspond to monophyletic groups in his AFLP analyses of S. nigrum or S. villosum. Several species amongst the Old World black nightshades have both glandular and eglandular populations and individuals (e.g. S. alpinum, S. nigrum, S. tarderemotum, S. villosum). Seithe (1962Seithe ( , 1979 showed that in most Solanum species, glandular trichomes are found on cotyledons and hypocotyls of seedlings and are lost as plants mature; she suggested that species with glandular trichomes were more "primitive". It is equally probable that the retention of glandular tips on trichomes is a simple paedomorphic character and that it has little taxonomic significance if not correlated with other characteristics. Modern developmental work has not been undertaken with morelloid trichomes, but work has been done with the glandular trichomes of tomatoes and their relatives (e.g. Bergau et al. 2015). These studies show that these trichomes are architecturally very invariable and suggest they play a role in pest defence through release of metabolites in response to insect contact. Local ecological and herbivore pressures may also play a role in the presence or absence of glandular trichomes in the morelloids; this may help explain the highly heterogenous distributions of glandular and eglandular individuals in the polymorphic species in this group.

Inflorescences
As with all species of Solanum, the inflorescence of members of the Morelloid clade is developmentally terminal and later overtopped by the leading axillary shoot so that it appears lateral. The basic structure is an unbranched or variously branched scorpoid cyme. Most members of the black nightshades have unbranched (simple) or merely furcate (once-branched) inflorescences, but in populations cultivated for fruit (e.g. S. scabrum, S. umalilaense, S. villosum), complex branching can occur, presumably through human selection for higher fruit production. Populations of S. americanum from Hainan Island in southern China with highly branched inflorescences have been described as a distinct species (S. merrillianum), but we consider these to be variants of the common S. americanum (see description of S. americanum). The degree of inflorescence branching in species of the group may also depend upon plant or inflorescence age (e.g. S. tarderemotum). In all Solanum species, the inflorescence expands from the tip producing flowers in a proliferating manner (Lippman et al. 2008).
All members of the group have distinct peduncles, usually somewhat longer than the distal flower-bearing portion, but inflorescence length and flower number vary both between and within species. Many species in the group have what are termed "sub-umbellate" inflorescences, where the flower-bearing rhachis is very short and the pedicels are all very closely spaced and congested at the very tip of the inflorescence. We use the term sub-umbelliform in the species descriptions for the extreme cases of this flower clustering. This inflorescence is not a true umbel, but is described as such in much previous literature, usually as an umbellate or subumbellate cyme (e.g. D'Arcy and Rakotozafy 1994; Edmonds and Chweya 1997;Edmonds 2012). Both peduncles and pedicels usually have pubescence that is similar to that of the stems and leaves or somewhat reduced distally.

Pedicels
Pedicels in flower are usually deflexed or spreading, but this can be very difficult to see in herbarium specimens. In fruit, pedicels are usually somewhat pendent from the weight of the berry, but are strongly (e.g. S. chenopodioides, S. tarderemotum) or weakly (e.g. S. nigrum) deflexed in some species. Solanum tarderemotum has the pedicels in fruit strongly bent at the base in an acute angle relative to the rhachis; this is a useful character for identification of herbarium specimens. Other species have markedly spreading pedicels in fruit (e.g. S. memphiticum). The abscission zone at the pedicel base in members of the Morelloid clade is at the very base and, if and when pedicels fall, the scars are generally flush with the rhachis. Pedicel persistence with fruit ripening is an important species character in this group. Ripe berries either fall or are taken from the plant with the pedicel still attached (e.g. S. opacum, S. tarderemotum) or the berry falls and the pedicel is left behind (e.g. S. americanum, S. nigrum, S. villosum). The presence of old pedicels can be useful for identification of non-flowering herbarium specimens.

Calyces
The calyx in all members of the Morelloid clade is 5-merous and synsepalous. The calyx tube is generally conical or occasionally somewhat elongate (e.g. S. memphiticum) and the lobes are extremely variable in size and shape from minute and deltate (e.g. S. umalilaense) to long-triangular (e.g. S. pseudospinosum). The position of the calyx lobes in fruit is an important identification character; they can be strongly reflexed (e.g. S. americanum, S. villosum), spreading (e.g. S. nigrum, S. tarderemotum) or appressed to the berry (e.g. S. opacum). The calyces of the weedy introduced species S. nitidibaccatum and S. sarrachoides are accrescent in fruit with the calyx lobes expanding to envelop almost the entire berry (several other New World members of the group also have accrescent calyces, see Särkinen and Knapp 2016).

Corollas
In common with most other species of Solanum, members of the Morelloid clade have 5-merous sympetalous corollas that are variously stellate. Floral mutants are often observed, where 4-6-merous corollas can occur on individual plants that are otherwise 5-merous (e.g. S. scabrum). Colour is generally white or pale violet-tinged, but anthocyanin pigmentation can vary depending on environmental growth conditions. In most species at least, some individuals (collections) with purple or violet flowers have been recorded. Solanum villosum often has distinctive dark purple coloration on the abaxial midvein of each corolla lobe. At the base of the corolla tube, there is a ring or irregular area of differently coloured tissue usually referred to as the "eye". In the species of the Morelloid clade, this is usually yellow or greenish-yellow and, in some species, the eye has darker brown or blackish-purple margins (e.g. S. nitidibaccatum). The colours of the eye usually disappear in herbarium specimens and are rarely noted on labels. This eye is usually similar in texture to the rest of the corolla and not shiny as occurs in the Dulcamaroid clade (see Knapp 2013) Corollas in the Morelloid clade are stellate to deeply stellate and corolla lobes are deltate to long-triangular. Solanum tarderemotum has deeply stellate corollas, with reflexed corolla lobes, while S. memphiticum has corollas with the lobes approximately the same length as the tubular portion and the lobes are not strongly reflexed at anthesis. These characters, particularly those of the degree to which corolla lobes are reflexed, can be very difficult to see in herbarium specimens. As is seen in many other groups of solanums (e.g. Dulcamaroid clade, ANS clade, see Knapp 2013;Knapp and Vorontsova 2016) where flowers last more than one day, the corolla lobes vary in the degree to which they are reflexed through the life of the flower. Lobes often are spreading on day one, become reflexed to strongly reflexed on subsequent days and, as the flower ages, become spreading again.
Corollas of members of the Morelloid clade are usually very small, in fact representing the tiniest flowers of any Solanum. Corolla diameter varies from 4-20 mm; S. nitidibaccatum has the smallest corollas and S. hirtulum and S. furcatum the largest in the group of species occurring in the Old World. Adaxial lobe surfaces are usually glabrous, while abaxial corolla lobe surfaces are variously papillate, with longer simple uniseriate trichomes on the margins and tips.

Androecium
The stamens of members of the Morelloid clade are ellipsoid and equal to very slightly unequal in size and length. The filament tube and filaments are variously pubescent adaxially. Most populations of S. memphiticum have completely glabrous filaments, but this is not completely consistent within the species; this was used as a species-specific character in Edmonds (2012). The trichomes on filaments are simple and uniseriate and usually weak-walled and tangled. The filament tube is generally very short to almost absent and free portion of the filaments distinct. Filament length in comparison to anther length is a useful character for distinguishing species. In most of the Old World species of Morelloids, the free portion of the filament is more or less equal to the anther length, but in some species pairs with otherwise similar anther length (e.g. S. americanum, S. opacum) differences in free filament length can be diagnostic (S. opacum has much longer filaments than S. americanum). The length of filaments can affect the biophysical properties of anther vibration and thus vibratile pollination (e.g. Timerman et al. 2014;Switzer and Combes 2017) and thus may be an important characteristic involved in speciation in this group.
Anthers of members of the Morelloid clade conform to the poricidal morphology of all other species of Solanum (see Knapp 2001). In common with other "non-spiny" solanums, the anther is ellipsoid and the terminal pore usually "unzips" during anthesis to become an elongate slit. The anthers are loosely connivent and not connected by either "glue" (as in S. dulcamara, see Glover et al. 2004) or elongate papillae (as in the tomatoes, see Peralta et al. 2008). Anther size is an important identification feature in the Morelloid clade and varies from less than 1 mm (S. americanum, S. opacum) to ca. 4 mm long (S. alpinum); in such small flowers, small differences can be very important.

Gynoecium
The gynoecium in members of the Morelloid clade is bicarpellate; the carpels are fused in a superior ovary with axile placentation. The ovary is glabrous and usually conical to globose. The flowers lack nectaries, as do all species of Solanum. The style is straight or slightly curved and usually sparsely to densely pubescent in the lower half to third where it is enclosed in the anther cone. It is usually exserted from the anther cone, but in some species (e.g. most populations of S. americanum, S. scabrum) only barely exceeds the length of the stamens. This may be related to self-fertilisation and thus self-compatibility, as has been observed in the tomatoes (Rick et al. 1977(Rick et al. , 1978(Rick et al. , 1979Rick and Tanksley 1981;Peralta et al. 2008), but all species of the Morelloid clade tested have been self-compatible (Edmonds 1979a;Schilling and Heiser 1979;Eijlander and Stiekema 1994;Olet 2004). None of the species of the Morelloid clade has heterostylous flowers, although the style length varies along the rhachis in some individuals of S. tarderemotum (see species description). The stigma is capitate and occasionally somewhat bilobed (e.g. S. alpinum, S. pygmaeum). The ovules are anatropous and non-arillate.

Fruits
As with all species of Solanum, the fruit is a bicarpellate berry. Fruits of members of the Morelloid clade are usually brightly coloured and juicy. Most species have globose berries, but those of S. villosum are usually somewhat longer than wide. Berry colour can be green (S. nitidibaccatum, S. opacum, some populations of S. tarderemotum), greenish-yellow or yellow (some populations of S. nigrum and S. villosum, S. palitans), bright orange (S. villosum) or varying shades of purple (many species); immature berries are usually described as green on herbarium labels. Colour polymorphisms are common in species of this group; both S. nigrum and S. tarderemotum, for example, have individuals and populations with green or purple berries and S. villosum has either yellow or orange berries. Schilling and Andersen (1990) suggested there may be an environmental effect on berry colour in S. villosum; accessions labelled as having yellow or orange berries in the field in India all had orange berries in cultivation. Manoko (2007) showed that mature berry colour (green or black) did not differentiate groups within S. nigrum. Despite this variation, berry colour is an important identification aid in this group, but is often not recorded on herbarium labels, especially of older specimens.
The pericarp (epicarp) of the berries is thin and either matte (e.g. S. chenopodioides, S. tarderemotum) or shiny (e.g. S. americanum, S. villosum). Surface characteristics are useful for species identification, especially when combined with other characters (see discussion of S. americanum). The mesocarp is always juicy and very liquid; these fruits are eaten by both birds and mammals (including people). In general, the mesocarp of fresh fruits is green or greenish-yellow, but in species with purple berries, it is sometimes purplish. In the cultivated S. scabrum, this may be related to human-mediated selection in Africa and, in China, where on Hainan Island people are beginning to cultivate S. americanum (S. Knapp, pers. obs.), coloured fruit pulp is selected for by local people. This character is rarely mentioned on herbarium labels.
Like some other groups of non-spiny solanum such as the Pachyphylla clade (Bohs 1998) and the Archaesolanum clade (Symon 1994), berries of members contain small, hard inclusions commonly referred to as stone cells, sclerotic granules or brachysclereids (Bitter 1911(Bitter , 1914. These concretions are composed of modified sclerenchyma cells with massively enlarged cell walls; the stone cells of pears and quinces (Rosaceae) are classic examples of this cell type. Neither their function nor their origin in Solanaceae is known. It has been suggested that stone cells may aid bird dispersal by protecting the seeds in the gizzard or by helping seeds to adhere to birds' legs or plumage . Bitter (1914) suggested that they existed in an evolutionary series in the family, with more "advanced" taxa lacking them altogether (e.g. the spiny solanums). Some members of the Archaesolanum clade (e.g. S. aviculare G.Forst. with an average of 12-55 seeds and 491-607 stone cells; Symon 1994) have more stone cells in each berry than seeds. In the Morelloid clade, these stone cells are usually quite small and are always round in shape, ca. 0.5 mm in diameter and brown to white in colour ( Figure 3). Stone cells can usually be easily seen in dried specimens without dissecting the berry (see Figure 1 in Bitter 1914); they appear globose and are often distinctly larger or smaller than the seeds. Sometimes stone cells of different sizes are found in the same berry, but this character is not consistent within species. The number of these is usually relatively consistent within a species and varies from absent (e.g. S. scabrum, S. villosum) to 1-4 (e.g. S. nitidibaccatum, S. memphiticum) to >10 (e.g. S. triflorum). Bitter (1914) reported that, in crosses involving Morelloid species with and without stone cells, hybrids had stone cells present in the fruit, indicating to him that this was an inherited character. Cultivated species (e.g. S. americanum, S. retroflexum, S. scabrum, S. villosum) tend to lack stone cells; this may be related to human-mediated selection.

Seeds
Members of the Morelloid clade have flattened seeds, like other solanums. Unlike other groups, however, they are usually tear-drop rather than kidney shaped, with the hilum and micropyle at one of the short ends of the seed. Seed size varies from 1-3 mm long, polyploid species usually have larger seeds than diploids (e.g. S. americanum seed size is 1-1.5 mm, while that of S. scabrum is 2-2.8 mm) and hence seed size is a good feature for distinguishing S. nigrum (hexaploid) from S. americanum (diploid). Seed number per berry in the Morelloid clade is generally quite high (Särkinen et al. 2015a), with usually 30-50 seeds in each berry. Some species, however, consistently have fewer seeds (e.g. S. pseudospinosum, S. retroflexum).
Seed coat morphology has been suggested as a useful character for species-level taxonomy in Solanum (Souèges 1907;Lester and Durrands 1984) and has been useful in delimiting groups in some clades (e.g. Geminata clade, Knapp 2002a). All of the Old World morelloid species have sinuate-walled (digitate) testal cells. The lateral walls of these cells of the outer epidermal layer develop lignified radial thickenings that form as hair-like structures (Souèges 1907;Lester and Durrands 1984;Axelius 1992;Peralta et al. 2008). When the outer wall of the epidermis is removed, either naturally (e.g. by passage through frugivore guts, see Barnea et al. 1990) or by enzymatic digestion (Lester and Durrands 1984;Knapp 2002a), seeds appear pubescent; seed measurements here include these projections. Edmonds (1983) examined seed coat patterns in some members of the Morelloid clade (species previously included in Solanum section Solanum) and found no useful variation for delimiting either species or species groups.

Chromosomes
Chromosome numbers in the Morelloid clade are variations on the base number of 12 (Table 1). The chromosomes are very small with an average size of 1.57 -1.81 µm (Melo et al. 2011); an unvouchered diploid accession grown in India (Bhiravamurty 1975) had median, submedian and subterminal centromeres. Chromosome staining showed that S. americanum and S. nigrum have a satellite chromosome pair (Rego et al. 2009;Melo et al. 2011). The Morelloid clade, along with the potatoes, is one of the few lineages in Solanum where polyploidy is common (see the section on Polyploidy and hybridisation below). DNA amounts in unreplicated gametic nuclei (C-values) vary between 1.03 pg (1,002 Mbp) in S. americanum (as S. nodiflorum) and 3.10 pg (3,032 Mbp) in S. nigrum (Bennett and Leitch 2012).
Many chromosome counts are reported for members of this group, often as unvouchered counts of "Solanum nigrum". In the species treatments, we only record counts that are based on identifiable material or those that are vouchered and for which we have verified the specimen in question. Chromosome counts recorded in floras (e.g. Hawkes and Edmonds 1972) without vouchers are not listed.

Habitats and distribution
Members of the Morelloid clade are plants of disturbed habitats and occur in landslides, along roads and stream, and at the edges of cultivated fields. Many of the species have very broad elevational ranges (e.g. S. americanum) and extremely broad distributions, but a few of the Old World species are localised endemics (e.g. S. alpinum, S. hirtulum, S. pseudospinosum) primarily of montane areas.
These localised endemics are all from recent (ca. Miocene age), volcanic mountain ranges and are all probably of recent origin. Solanum pseudospinosum is a polyploid, while the ploidy levels of S. alpinum and S. hirtulum are not known. Molecular data suggests S. hirtulum to be a polyploid based on presence of multiple peaks in low copy nuclear gene sequences, similar to known polyploid species such as S. nigrum (Särkinen et al. 2015a). Geology and origins of the floras of these mountain ranges are discussed in the individual species treatments.
Several members of the group (e.g. S. nigrum, S. nitidibaccatum) are registered as noxious weeds of agriculture (see below) in both Europe and North America Defelice 2003). Solanum triflorum is listed as a declared weed in Tasmania (Weed Management Act 1999. Many herbarium collections from Africa record morelloid species as "weeds on edge of agriculture", but it is often unclear whether these were really weedy or were being cultivated using local traditional methods (see Uses below). Confusion over the identification of individual species  and the common use of "S. nigrum agg." in describing these species makes assessment of their status very difficult in the absence of vouchers.
We list the status and general distribution of the species in the group in Table 2  and, in Tables 3-6, document country distribution for Africa (Table 3), Asia (Table 4), Europe (Table 5) and the Pacific (Table 6) from herbarium specimens (see Materials and Methods).

Pollination and dispersal
Like most solanums, flowers of members of the Morelloid clade are buzz-pollinated by bees (Buchmann et al. 1977;De Luca and Vallejo-Marín 2013). Females of solitary bees and bumblebees vibrate the anthers with their indirect flight muscles causing pollen to "squirt" out of the terminal pores; they curl their bodies over the anther cone and rotate around the flower (Buchmann et al. 1977). The pollen is then groomed from the body and packed into the corbiculae, but the area of the venter that contacts the stigma of the next flower cannot be reached. Smaller bees visit and buzz individual anthers (Symon 1979), but do not usually contact the stigma and thus solanums with large flowers are more properly seen as pollen thieves. Some bees also exhibit "milking" behaviour, where insects grasp the lower part of the anthers and try to force pollen out of the apical pores using upwards pressure (Buchmann et al. 1977. "Gleaning" of loose    (Pawłowskiego 1963;Natkevičaitė-Ivanauskienė 1976;Bertová and Goliašová 1993;Hämet-Ahti et al. 1998;Fischer et al. 2005;Jauzein and Nawrot 2011;Hartvig 2015;Rottensteiner 2015). Countries where these species are expected to occur, but from which we have seen no specimens are included, but no species listed.  pollen grains is also done by various small bees and flies (Symon 1979;Knapp 1986). Buchmann et al. (1977) (Knapp 2002b). Studies of dispersal of morelloid species have mostly been done on the species occurring in the United States of America (e.g. Tamboia et al. 1996) with native bird and mammal frugivores (quail, American robins and deer mice). Bravo et al. (2014) record great bustards as frugivores and seed dispersers for S. nigrum in central Spain and Barnea et al. (1990) record blackbirds and bulbuls as frugivores of both S. nigrum and S. villosum (as S. luteum) in Israel. Green fruits are expected to be more attractive to mammals, but Tamboia et al. (1996) found that both birds and mammals preferred the purple berries of S. americanum to the green berries of S. sarrachoides (probably = S. nitidibaccatum, no vouchers cited). The suite of characters expected to be attractive to mammals such as green colour, odour and abscission shortly after ripening are all found in some of the Old World morelloids such as S. tarderemotum and suggests that mammals may be important fruit dispersers for some of these species as well. Only a few ecological studies have been done on the Old World species of morelloids in their native habitats (but see Barnea et al. 1990;Bravo et al. 2014), although there are many anecdotal references to their dispersal by birds. The ecological interactions are likely to be similar to those observed in North America. Glycoalkaloid concentrations are very low in ripe berries of S. americanum and other members of the Morelloid clade that have been tested (Cipollini et al. 2002) and levels are similar across the clade. Higher concentrations in unripe fruit (Cipollini et al. 2002) of these species make them unattractive to frugivores (Cipollini and Levey 1997a). This loss of secondary metabolites in ripe berries is common across Solanum species with brightly coloured, fleshy fruits (e.g. Bradley et al. 1979) and is most likely related to fruit persistence (Cipollini and Levey 1997b), where risk of fungal infection is balanced by probability of animal ingestion and thus dispersal. Glycoalkaloids are known to have a constipative effect (see above, e.g. Gerard 1597) and to inhibit seed germination after ingestion (Cipollini and Levey 1997b), but Wahaj et al. (1998) found that ripe berries of S. americanum had a laxative effect on birds thus speeding seed passage through the gut. They suggested this was due to some other chemical compound (perhaps calystegines (?), see Dräger et al. 1994). Solanum nigrum germination was not affected by ingestion by bulbuls and blackbirds (Barnea et al. 1990), but germination was enhanced in S. villosum (as S. luteum). Barnea et al. (1990) suggest this is due to the more arid habitats in which S. villosum grows, where bird defecation around shrubs would enhance survival of seedlings. Bravo et al. (2014) showed that germination rates for S. nigrum were lower after ingestion by great bustards, but still concluded that the birds were likely to be efficient seed dispersal agents.

Conservation status
Most Old World morelloid species are weedy and widely distributed; many are also cultivated (e.g. S. tarderemotum, S. scabrum, S. villosum) and are distributed widely via human migration. Many introductions of species to Europe have resulted from the use of wool shoddy as protection in market gardens (Blom 1935;McClintock 1977) but even casual visitors to far-flung places have been implicated in the introduction of alien species (Chown et al. 2012). It is likely that the early explorations of the southern Hemisphere inadvertently carried seeds of nightshades with them, accounting for the widespread nature of many of these taxa. The genetic structure of populations of extremely widespread species such as S. americanum will need to be investigated to determine if a structure exists in the distribution that can be related to natural or human-mediated causes.
The range-restricted endemic species of Old World morelloids suffer from taxonomic recognition issues that could seriously affect their conservation. In recent floras of many parts of the world, all taxa are treated as a single highly variable species (usually S. nigrum) and local endemic taxa are overlooked and equated with widespread invasive weeds. This means that these endemic taxa have possibly been placed at risk. Preliminary conservation assessments for the Old World members of the Morelloid clade (including introduced taxa) are presented in Table 7. Conservation status for introduced taxa includes worldwide data, from both native and introduced ranges.

Polyploidy and hybridisation
The Morelloid clade is one of only a few cases of extensive ploidy level variation in Solanum. Potatoes and the Archaesolanum clade are the only other clades of Solanum in which ploidy level variation is extensive Spooner et al. 2014); due to the economic importance of the species in the Potato clade as contributors of genes for cultivated potato improvement, they have been much more extensively investigated than the morelloids (see Spooner et al. 2014). Potato species are also diploid, tetraploid or hexaploid, but the cultivated potato itself (S. tuberosum L.) comprises both diploid and tetraploid populations (see Spooner et al. 2007); this variation of ploidy level occurs in some New World morelloids, but we have not observed it in the species treated here. The morelloids have been the focus of only a few previous studies (e.g. Stebbins and Paddock 1949;Edmonds 1977Edmonds , 1979a (Heiser 1963;Edmonds 1977) and three species (S. interandinum Bitter, S. macrotonum Bitter, S. pygmaeum) appear to have multiple ploidy levels. Eight of the Old World native morelloids are polyploid (six tetraploids and two hexaploids) and sequence data indicate that S. hirtulum is also a polyploid based on the presence of multiple double peaks in low copy nuclear sequence reads similar to known polyploid species (e.g. S. nigrum), but this needs to be confirmed with a vouchered chromosome count (see Table 1; Särkinen et al. 2015a). The ploidy level of S. alpinum remains unknown. Natural hybridisation between sympatric species (Ganapathi andRao 1985, 1986b) has been suggested as the reason for the large number of polyploids in the Morelloid clade, especially in the Old World, but evidence for this hypothesis is weak at best. It is thought that most of the polyploids in the Morelloid clade are of alloploid, rather than autoploid origin, because bivalents show regular pairing at meiosis (Edmonds 1977(Edmonds , 1979aGanapathi and Rao 1987a;Ojiewo et al. 2007). The putative parental origin of these species has been investigated using traditional crossability and hybridisation techniques (Edmonds 1977;Ganapathi and Rao 1985, 1986b, 1986c, 1986d, 1987a, 1987b and, more recently, using molecular markers (Manoko 2007;. Chromosome painting or GISH (genomic in situ hybridisation) techniques have not been used in determining progenitor genomes in the morelloids as they have with great success in Nicotiana (e.g. Chase et al. 2003;Clarkson et al. 2005) and in the potatoes (e.g. Pendinen et al. 2012). Edmonds (1977) undertook an extensive crossing programme involving morelloid species from both the New and Old Worlds. She found that hybridisation was relatively common within ploidy level, while successful hybridisations between ploidy levels were rare. Successful crosses between tetraploids and hexaploids were postulated to have resulted due to possession of a common parental genome. She suggested that S. sarrachoides (as S. sarachoides) was a potential diploid parent of S. nigrum, because almost half of the crosses involving it and S. nigrum were successful; she also stated that S. americanum was the "undisputed [diploid] progenitor" of S. nigrum, probably based on the work of Nakamura (1935Nakamura ( , 1937. Regular bivalent pairing in hybrids derived from S. nigrum × S. scabrum crosses indicate homology of parental genomes of the two hexaploids (Ganapathi and Rao 1987a). Evidence from other crossing studies suggests that the tetraploid S. villosum, S. retroflexum or one of their close relatives, has also been involved in the parentage of S. nigrum (Ganapathi andRao 1986b, 1986c) and that S. villosum is one of the parents of S. scabrum (Ganapathi and Rao 1985, 1987a, 1987b. As only a limited set of the diploid and tetraploid species have been used in these crossing studies, results have to be interpreted with care in that the species tested, or any of its close relatives, could have been involved in the parentage. Detailed molecular phylogenetic studies could help to reveal closely related species to the ones used in these crossing studies to further understand potential parents that could then be tested. Manoko (2007) used AFLP (Amplified Fragment Length Polymorphism) molecular markers to examine genetic variation within and between African diploids and polyploids. As AFLP analyses are based on fragment sizes, results from these analyses only allow us to understand genetic variation but do not directly link to phylogenetic relationships. The AFLP study found that tetraploid accessions split into two distinct groups; a set of tetraploids (group A; S. retroflexum, S. tarderemotum (as S. florulentum), S. umalilaense and S. villosum) clustered with hexaploid taxa (S. nigrum, S. scabrum) and another set (group B; S. memphiticum, S. tarderemotum and "S. patens") clustered with diploid species used in the analysis. It was suggested that, because the tetraploids split into two clear groups in a Neighbour Joining (NJ) analysis, they were unlikely to share diploid progenitors (Manoko 2007), but as highlighted above, AFLP studies allow the inspection of genetic variation but not phylogenetic relationships.  used ISSR (Inter Simple Sequence Repeat) and SCoT (Start Codon Targeted) markers in a network analysis to investigate the origin of S. nigrum. They used a limited number of species that had previously been suggested as having common origins; S. americanum, S. chenopodioides, S. nigrum, S. opacum, S. nitidibaccatum (as S. physalifolium Rusby) S. retroflexum, S. scabrum and S. villosum. Their results supported the close relationship between S. villosum and the two hexaploids (S. nigrum and S. scabrum) and they suggested that these species share a diploid progenitor. They also showed that S. villosum is most likely an autotetraploid derived from S. americanum, confirming an earlier chromosome banding study (Sultana and Alam 2007) and hypothesised that the progenitors of S. nigrum are S. villosum and S. americanum and that the species evolved via amphiploidy of sterile triploid progeny . Solanum opacum and S. retroflexum were associated with S. chenopodioides and S. nitidibaccatum (as S. physalifolium) and not with S. americanum, contrary to suggestions by Edmonds 1977, who thought S. americanum was involved in the origins of S. retroflexum based on crossability, suggesting their diploid progenitors are not shared with the other polyploids in the analysis. Results of previous work attempting to establish genome origins for morelloid polyploids is summarised in Table 8.
The species of black nightshades are predominantly self-compatible (Edmonds 1979a;Schilling and Heiser 1979;Olet 2004). Interspecific crosses can be produced between most species within ploidy levels, although fertility is not always high and some breeding barriers exist (Edmonds 1977(Edmonds , 1979aOlet 2004). Putative hybridisation in the wild has been reported between co-occurring diploid species in North America and Australia (Stebbins and Paddock 1949;D'Arcy 1974b;Henderson 1974). Schilling and Heiser (1979), however, suggested that the ability to cross was not a useful taxonomic character in the morelloids. Natural hybrids have also been reported between diploids and polyploids and between polyploids themselves (Henderson 1974;Leslie 1978;Venkateswarlu and Rao 1972), although Edmonds (1977) showed that within ploidy level crossability success was much higher than that between ploidy levels. Hybridisation, followed by backcrossing to parental species and/or polyploidisation, has been thought to explain some of the complex morphological variation found within the group (Stebbins and Paddock 1949;Edmonds 1979a). This assumption of widespread hybridisation being responsible for taxonomic complexity was also the case for the potatoes, but detailed studies with modern methods have shown that much of the variation is not due to hybridisation but instead to extensive within-population variability (Spooner et al. 2014). Schilling and Heiser (1979) pointed out that the hybrids created in the greenhouse were unlikely to occur in nature and expressed views that the use of the Biological Species Concept (BSC; e.g. Mayr 1982) in this group where most species are interfertile at some level is not useful (see Knapp 2008 for a discussion of the BSC and plant species recognition).

Chemistry
There is considerable confusion regarding the toxicity of species of black nightshades (see Schilling et al. 1992;Olet et al. 2005). Many manuals or floras list black nightshade berries as toxic (e.g. Kingsbury 1964;Edmonds 2005). The European members of the group are often confused with the deadly nightshade Atropa bella-donna L., whose berries are similarly black and shiny, but contain highly toxic tropane alkaloids such as atropine and scopolamine (Parr et al. 1990;Ashtiana and Sefidkonb 2011).
No species of Solanum has been shown to contain tropane alkaloids such as atropine or scopolamine (Tétényi 1987;Pigatto et al. 2015), but members of Solanum, including the black nightshades, do contain the nortropane alkaloids known as calystegines (Dräger et al. 1994;Pigatto et al. 2015). In Solanaceae, these compounds are synthesised along the same pathway as the tropanes, but are not as toxic when tested on laboratory rats (Stegelmeier et al. 2008); the finding that they occur in many commonly eaten foods suggests their activity differs from that of the tropanes such as atropine, scopolamine and nicotine (Asano et al. 1997;Welch et al. 2012). Most species of Solanum contain a wide range of steroidal alkaloids (also known as glycoalkaloids; Bradley et al. 1979) that, while potentially toxic in very large quantities, are not dangerous to humans. Chemical surveys have shown that only unripe fruits contain these potentially somewhat toxic glycoalkaloids (Cipollini et al. 2002), while leaves and ripe fruits usually lack these compounds (Carle 1981;Voss et al. 1993).
Many of the studies that have studied the chemical composition of morelloid species have mixed samples of immature and mature berries, leading to conclusions that berries are poisonous (Eldridge and Hockridge 1983;Mathé et al. 1980;Sharma et al. 1983;Arnold 1985). Such findings are important in agricultural trade where species of morelloids occur as weeds and their immature and mature berries are eaten by livestock and can contaminate harvests of a variety of grain and vegetable crops Rogers and Ogg 1981). Toxicity of unripe berries, however, appears to be reduced if forage is fermented as silage (Vogel and Gutzwiller 1993) and does not apply when ripe berries are harvested for human consumption.

Uses
Species of black nightshades are used as leafy vegetables or fruits throughout the world, sometimes referred to as 'supervegetables' for their high protein and iron content (FAO 1988;Yang and Ojiewo 2013;Cernansky 2015;Ronoh et al. 2017;Fokon and Domugang 1989). Species of the group are wild-harvested or cultivated for their juicy berries in both the Old and the New Worlds, in both the tropics and temperate zones (e.g. Heiser 1969). Their use, however, has been particularly studied in Africa, where they are important components of indigenous cultivation systems (Edmonds and Chweya 1997;Schippers 2000;Keding et al. 2007;Pasquini et al. 2009) and are the focus of plant breeding strategies aimed at improving the nutrition and income generation of women and children in urban and peri-urban areas (Dinssa et al. 2016;Manoko andvan der Weerden 2004a, 2004b).
In Africa, species are cultivated either for use as leaf vegetables (e.g. S. americanum, S. memphiticum, S. scabrum, S. tarderemotum, S. umalilaense, S. villosum) or for their fruits (e.g. S. americanum, S. retroflexum, S. scabrum, S. villosum). Leaves of African nightshades are high in flavonoids, vitamin C, folates, iron and antioxidants (Akubugwo et al. 2007;Keding et al. 2007;Yang and Ojiewo 2013;Ronoh et al. 2017) and the leaves are often cooked in milk to make them less bitter. Medicinal uses in Africa include antiseptic for eyes and skin, treatment of diarrhoea (Essou and Hermans 2006) and as a general tonic for health (Yang and Ojiewo 2013). Seeds have been found to be rich in lipids and a good source of essential fatty acids used in some areas in Africa (Nzikou et al. 2007).
In Asia, including the Indian subcontinent, S. nigrum is also used as a leaf vegetable (Arora 1981;Jain and Borthakur 1986), for its fruits (Abraham 1981;Vartak 1981) and in medicine (Ammaan and Subramanian 2017). Berries of several species are eaten (e.g. S. americanum, S. retroflexum, S. scabrum, S. villosum; see also individual species treatments). Solanum nigrum is mentioned in several different contexts in the 13 th century Chinese treatise Jinhuang Bencao which was the first of many Chinese works on uses of plants and introduced many plants into the diets of modern Chinese people (Zhu et al. 2015). In that work, it is mentioned both as a food (leaves and berries) and as a medicine. Today, leaves of morelloid species are commonly eaten, particularly in southern China; one of the authors (S. Knapp, pers. obs.) has also observed cultivation of S. americanum for its fruits there.
Disaggregating uses for these species is difficult because many authors treated all morelloids as a single, highly variable taxon; Burkhill (2000) treated all morelloids in western Africa as S. americanum, while they were most certainly several species. The cultivated status of many of these plants went unnoticed by many early plant collectors, who often noted them as "weeds of field margins". Black nightshades are known by a great many indigenous names, especially across Africa and care must be taken with names applied to species in literature, given the complex taxonomy of the group and difficulties in transliteration of indigenous languages by early collectors. In Table  9, we list the more widely encountered common names by region and language and, in each individual species treatment, list those that we have verified for each species from either herbarium specimens or from literature where we are certain of the species identification.
Solanum scabrum is by far the most commonly cultivated of the Old World species and is cultivated throughout Africa (Berinyuy et al. 2002;Defelice 2003;Bukenya and Carasco 1995;Olet et al. 2006), especially in western Africa. It is also known from the Caribbean where it was most likely brought by enslaved peoples from western Africa. In the United States, S. scabrum was marketed under the name of "Garden Huckleberry" (Soria and Heiser 1959), where it was introduced with great fanfare by the vegetable breeder Luther Burbank (Heiser 1969). Burbank also introduced what he called a new species, the "Sunberry", later marketed as the "Wonderberry", which turned out to be the southern African species S. retroflexum (Soria and Heiser 1959;Heiser 1969); Burbank claimed he had created it from a cross between S. scabrum and what he called S. villosum (probably = S. sarrachoides). The story of this and the accusations that Burbank was marketing a poisonous plant are well-documented in Heiser (1969).
Solanum tarderemotum and S. villosum are more commonly cultivated in eastern Africa and many specimen labels note that the fruits of S. villosum are particularly prized by children (also see Keding et al. 2007). Solanum umalilaense is cultivated locally as a leaf vegetable in the Umalila region of Tanzania (Schippers 2000;Manoko andvan der Weerden 2004a, 2004b) and its highly branching morphology is perhaps due to human selection. In Asia, S. villosum, S. americanum and S. nigrum are all used for both their berries and leaves, as well as for medicine (Potawale et al. 2008;Jagatheeswari et al. 2013). Details of cultivars and more specific uses are given in the species treatments.
Solanum "nigrum" has a long history of use in Ayurvedic medicine in India, but it is clear that the concept medicinally does not distinguish between S. nigrum s.s. and S. villosum (see Warrier et al. 1996;Jagatheeswari et al. 2013;Ved et al. 2016). The plants are noted for their antiseptic and antidysenteric properties and, in common with other members of the family, are considered to be febrifuges and anti-inflammatories (see Dunal 1813). They have been used in the treatment of many different diseases and complaints in many areas of the Old World (e.g. Dunal 1813; Grieve 1931;Huang 1993;Ghazanfar 1994;Edmonds and Chweya 1997;Burkhill 2000). Early European Table 9. Widely used common names for black nightshades in the Old World. Where names can be confidently assigned to individual species, these are listed in the species accounts. We only include names here from which the language is available and unambiguous; many common names in the literature are taken from herbarium labels and both the original and transcription are often very dubious. Sources include Degener (1945), Edmonds and Chweya (1997), Schilling et al. (1992), D'Arcy and Rakotozafy (1994), Ghazanfar (1994), Warrier et al. (1996), Burkhill (2000), Hul and Dy Phon (2014), Ignacimuthu et al. (2006), Euro+Med (2006-), Almeida and Almeida (2008), Ved et al. (2016) and BSBI (2017).

Region
Name ( uses are documented in the herbals (see above) and in the many pharmacopoeia of different countries (summarised in Grieve 1931); Dunal (1813) records S. nigrum as being the most used of European species of Solanum, and that with the most ancient use (dating back to Hippocrates, Dioscorides and Theophrastus). Common properties appear to be antiseptic, anti-inflammatory, expectorant and diuretic and these plants are often cited for the treatment of eye and stomach complaints (e.g. Ignacimuthu et al. 2006). In Europe, seed remains of S. nigrum have been excavated from the Viking layers at York (Kenward and Hall 1995) and at ten other sites in Denmark, Germany, Ireland, Russia and Sweden (A. Poulsen and A. Kool, pers. comm., manuscript in preparation). Solanum villosum has been found in Israel in Acheulian site in Gesher Benot Ya'aqov, amongst other food plants that were used by early humans (Melamed et al. 2016). The excavated seeds that represent the black nightshade species still in use today demonstrate that their use has been widespread across different cultures and areas dating back to early humans during their migration out of Africa in mid-Pleistocene (Melamed et al. 2016).
In the Pacific, uses for black nightshades (S. americanum and S. opacum, without distinction) are recorded from Hawaii (Degener 1945). As with other species of the group, both leaves and berries are eaten and used medicinally. Medicinal uses recorded are as an antiseptic, laxative (the juice of the plant) and as a tonic (Degener 1945); bruised leaves are used topically for stomach ache.
Glycoalkaloids from S. americanum, S. nigrum and S. opacum were often used as a steroid base for human contraceptives until the industry moved to production of synthetic compounds in the 1980s (Bradley et al. 1979;Carle 1981). Aqueous extract from S. villosum (as S. alatum) and S. nigrum have been shown to exhibit anti-inflammatory, hepato-protective, anti-cancer effects and potential to control and prevent gastric ulcers (Lin et al. 1995;Heo and Lim 2005). Leaf extracts of several morelloid species have been shown to have a molluscicidal effect against Bulinus (Ndamukong et al. 2006) and Biomphalaria (El-Sherbini et al. 2009) snails that act as hosts of Schistosoma parasites that cause the tropical disease bilharzia (schistosomiasis) and against the parasites themselves (Obare et al. 2016). On the Indian subcontinent (Singh et al. 2001), tests of leaf extracts of S. nigrum have shown promise as larvicides against mosquitoes that are important vectors of human disease such as the malaria vector Anopheles culicifecies Giles and the filariasis vectors Culex quinquefasciatus Say and Aedes aegypti (Linnaeus in Hasselquist). Extracts from the berries of S. villosum offer promise as biocontrol agents for the mosquito dengue fever vector A. aegypti (as Stegomyia aegypti) since resistance to commonly used insecticides is on the increase in many parts of the developing world (Chowdhury et al. 2008). The steroid alkaloid solanine from S. americanum has been used as an agricultural pesticide (Sumner 2000) and produces a proteinase inhibitor (PI II) that has shown to confer insect resistance in transgenic plants (Xu 2001).
Old World species of the Morelloid clade are also sources of resistance genes used in agriculture. Several species of black nightshades, including S. nigrum, S. americanum and S. villosum, are known to carry resistance genes against late blight (Phytophthora infestans (Mont.) de Bary), a major fungal pest in potato, tomato and eggplant (Kamoun et al. 1999;Campos et al. 2002;Flier et al. 2003;Lebecka 2008Lebecka , 2009Śliwka et al. 2012;Witek et al. 2016). Although resistance traits have been transferred to potato (S. tuberosum L.) in some experiments (Colon et al. 1993;Eijlander and Stiekema 1994;Horsman et al. 1997;Zimnoch-Guzowska et al. 2003), black nightshades have not been widely used in traditional plant breeding, but new cloning techniques coupled with the large number of resistance genes found in S. americanum suggest these plants hold promise for biotechnology (Witek et al. 2016). Solanum nigrum has also been used as a model system with which to study herbivore defence responses (Schmidt et al. 2004), especially since response chemistry seems to differ significantly from that seen in tomato (Schmidt and Baldwin 2006).

Species concepts
Our goal for the treatment of the Old World species of the Morelloid clade has been to provide circumscriptions for the members of this morphologically variable group of species, while clearly highlighting areas, taxa and populations where further in-depth research is still needed to confirm current taxon concepts. Delimitation of species here basically follows what is known as the "morphological cluster" species concept (Mallet 1995): i.e. "assemblages of individuals with morphological features in common and separate from other such assemblages by correlated morphological discontinuities in a number of features" (Davis and Heywood 1963). Biological (Mayr 1982), phylogenetic (Cracraft 1989) and the host of other finely defined species concepts (see Mallet 1995) are almost impossible to apply in practice and are therefore of little utility in a practical sense (see Knapp 2008). It is important, however, to clearly state the criteria for the delimitation of species, rather than dogmatically follow particular ideological lines (see Luckow 1995;Davis 1997). Our decisions relied on clear morphological discontinuities to define easily distinguished species. Specific characters used for recognition are detailed with each species description and in the key. Some potential reasons for variability and intergradation are recent divergence, hybridisation and environmental influence on morphology. In this revision, we have tried to emphasise similarities between populations instead of differences, which so often reflect incomplete collecting or local variation. We have not recognised subspecies or varieties, but have described and documented variation where present, rather than formalise such variability with a name which then encumbers the literature. We have been conservative in our approach, recognising as distinct entities those population systems (sets of specimens) that differ in several morphological characteristics. Many of the species in the group (and of Morelloids in general) are extremely widespread and variable; variation exists in certain characters, but the pattern of variation is such that no reliable units can be consistently extracted, nor is geography a completely reliable predictor of character states. Here variability within and between populations seems more important than the variations of the extremes that other taxonomists have recognised as distinct. We describe this variation realising that others may wish to interpret it differently.
Although infraspecific taxa have been recognised by others within the group, we do not recognise any here due to the complex morphological variation observed within each species, where the inspection of a larger number of specimens quickly reveals no apparent natural breaks in variation but rather a mixing between highly morphologically variable populations of widespread species. Results from seed protein studies (Edmonds and Glidewell 1977), as well as from more recent population genetic studies (e.g. Manoko 2007;Manoko et al. 2008) support our morphological observations in finding no obvious patterns supporting infraspecific structure within particular variable species such as S. americanum, S. villosum and S. nigrum.

Materials and methods
Our taxonomic treatment is based on results from recent molecular systematic studies considering the taxonomy of the section, including focused morphological and AFLP studies of the African species by Jacoby (2003: South Africa), Olet (2004) and Manoko (2007), network analysis of the polyploid species and their putative diploid ancestors by   Measurements were made from dried herbarium material supplemented by measurements from living material. Colours of corollas, fruits etc. are described from living material or from herbarium label data. Specimens with latitude and longitude data on the labels were mapped directly. Some species had few or no georeferenced collections; in these cases, we retrospectively georeferenced the collections using available locality data. Maps were constructed with the points in the centres of degree squares in a 1° square grid. Conservation threat status was assessed following the IUCN Red List Categories and Criteria (IUCN 2016) using the GIS-based method of Moat (2007) as implemented in the online assessment tools in GeoCat (http://geocat.kew.org). The Extent of Occurrence (EOO) measures the range of the species and the Area of Occupancy (AOO) represents the number of occupied points within that range based on the default grid size of 2 km 2 . We present only the EOO in the threat assessments for widespread species; AOO is very sensitive to georeferencing bias. For introduced taxa we also present their conservation status in the putatively native range in each of the species treatments.
Type specimens in this group have proved difficult to trace. Many taxa were described based on types housed in herbaria whose collections were lost during the Second World War, including the Berlin herbarium (B) (see Vorontsova and Knapp 2010). In our searches of many potential repositories for original material, we have been able to trace duplicates for at least some of these. For taxa recognised only as synonyms, we have cited the taxa in synonymy and indicated that duplicates have not been found rather than neotypifying these (often infraspecific) taxa. We have also made use of specimen images available via online databases: BP (for the herbarium of Pál Kitaibel, https://gallery.hungaricana.hu/hu/Herbarium/), G (http://www.villege.ch/cjb/bd.php), P (https://science.mnhn.fr/institution/mnhn/collection/p/item/ search/form), W (http://herbarium.univie.ac.at/database/search.php), Z (http://www. herbarien.uzh.ch/index.html), the African Plants Initiative and Global Plants (http:// plants.jstor.org).
Many of the species and infraspecific names coined for European plants in the 19 th and early 20 th century floristic and other works have no specimens cited. In some cases, we have been able to trace potential original material, but in others, plants may have been described from living material. We have lectotypified these names where we have been able, but have not selected neotypes for those names that have rarely been used beyond their first description (mostly infraspecific taxa of S. nigrum and S. villosum). Where specific herbaria have not been cited in protologues, we have followed McNeill (2014) and designated lectotypes rather than assuming holotypes exist. We cite page numbers for all previous lectotypifications. In general, we have lectotypified names with the best preserved, or in some cases only, herbarium sheet we have seen; in these cases, we have not outlined our reasoning for the letotypifications. Where there has been difficulty or where the choice may not be obvious, we detail our reasoning at the end of the species discussions.
The amateur Czech botanist, Paul M. Opiz, collected prolifically and described many taxa based on his and other collections, most of these specimens being housed in PR or PRC (Kirschner et al. 2007). We have been unable to visit those collections during the course of this work, so have not lecto-or neotypified these names.
Georg Bitter (e.g., 1913aBitter (e.g., , 1917Bitter (e.g., , 1921Bitter (e.g., , 1923 described many taxa of Solanum in the course of his monumental work on African solanums and worked widely in Germany in the period between the two World Wars (Weber 1928), including, but not exclusively, at Berlin. His protologues frequently include specific herbarium citations, but not in all cases. We have cited specimens as holotypes only when a single specimen with a single herbarium citation is indicated in the protologue; we have not assumed his types are all in B. Edmonds (1972Edmonds ( , 1979b cited as "holotype" specimens at single herbaria that are in fact more correctly cited as lectotypes; we have accepted these as effective lectotypifications (Art. 7.10, McNeill et al. 2012) but corrected her citation of "holotype" to lectotype. D'Arcy (1974a) cited "type", "syntype" or "lectotype" for many of the names treated here in his treatment of Solanum for Flora of Panama. He explicitly cited some of these as "lectotype" and we treat these as validly published lectotypifications because his intention was clear. We also treat his citations as "type" coupled with the citation of a single herbarium as unintentional ("inadvertent") lectotypifications (e.g. Prado et al. 2015), following the stipulations of Art. 7.10 of the Code . We have tried to find previous lectotypifications to the best of our ability, but some done inadvertently in floras may have escaped our notice.
Type specimens are cited with their barcodes in square brackets after each herbarium code, written as they are spelled with barcode readers, either as a continuous string (i.e. [G00104280]) or with a dash (i.e. [MO-1781232]) depending on the style of barcode used in each herbarium. Sheet numbers are cited where barcodes are missing and these are indicated as distinct from barcodes (i.e. MO [acc. # 1037660]). For widespread species, we have not cited geographically representative specimens in the text under each species treatment, but instead listed the countries of occurrence by region (Africa, Asia, Europe, Pacific [incl. Australia]; also see . Identities of all numbered collections seen for this study are in Supporting Material (Appendices 1-3, including Index to numbered collections and specimens cited in pdf, xls and csv formats). The full searchable specimen details are also available on the Solanaceae Source website (www.solanaceaesource.org) and in the dataset for this study deposited in the Natural History Museum Data Portal (https://doi.org/10.5519/0009648). For narrowly endemic taxa, we have cited all the specimens we have examined. For introduced taxa, we cite only Old World specimens in this treatment, but the data set on the NHM Data Portal (https://doi.org/10.5519/0009648) includes all material seen for these species, including New World collections examined for globally distributed species.
Citation of literature follows BPH-2 (Bridson 2004) with alterations implemented in IPNI (International Plant Names Index, http://www.ipni.org) and Harvard University Index of Botanical Publications (http://kiki.huh.harvard.edu/databases/publica-tion_index.html). Following Knapp (2013), we have used the square bracket convention for publications in which a species is described by one author in a publication edited or compiled by another, the traditional "in" attributions such as Dunal in DC. for those taxa described by Dunal in Candolle's Prodromus Systematis Naturalis Regni Vegetabilis. This work is cited here as Prodr. [A.P. de Candolle] and the names are thus attributed only to Dunal. For "ex" attributions, we cite only the publishing author, as suggested in the Code . Standard forms of author names are according to IPNI (International Plant Names Index, http://www.ipni.org).
Common names and uses given under each species treatment are recorded for verified specimens only. The aim here is to provide an authoritative summary; further details on uses and names can be checked from the literature cited. Similarly, we refer to chromosome counts based on voucher specimens that we have been able to verify or based on studies that describe the voucher material in adequate enough morphological detail that allows us to draw firm conclusions on the identity of the original material. This means that some studies (e.g. Venkateswarlu and Bhiravamurty 1969) have been excluded.

Taxonomic treatment
The Morelloid clade sensu Bohs (2005) and Särkinen et al. (2013Särkinen et al. ( , 2015a Solanum section Dulcamara (Moench) Dumort. subsect. 2 "herbaceous plants confined to the central Andes" of Nee (1999: 295) [includes the species of Child's section Parasolanum excluding the type]. Solanum section Solanum subsects. 1 "Solanum", 2 "Glandular pubescent group", 3 "Campanulisolanum", 4 "Chamaesarachidium" and 6 "Episarcophyllum" of Nee (1999: 306-308), excluding his subsect. 5 "Gonatotrichum" [now recognised as being part of the Brevantherum clade, see Stern et al. 2013 Description. Herbs, occasionally woody at the base; unarmed. Stems terete or angled, sometimes hollow, lacking true prickles but sometimes with prickle-like processes along the angles, glabrous or pubescent with simple or branched (only in the Americas) uniseriate trichomes, these eglandular or glandular. Sympodial units difoliate or trifoliate, the leaves usually not geminate. Leaves simple with entirely or variously dentate or lobed margins or occasionally deeply pinnatifid, concolorous, glabrous to densely pubescent with eglandular and/or glandular simple or branched (only in the Americas) uniseriate trichomes; petioles well developed or not, the leaves never sessile. Inflorescences opposite the leaves or arising internodally, unbranched or many times branched, not bracteate (except in S. triflorum where a single bracteole sometimes present), with few to many (up to 100) flowers; peduncle various, usually not longer than the inflorescence branches; pedicels articulated at the base. Flowers 5-merous, actinomorphic to very slightly zygomorphic, all perfect. Calyx with the lobes deltate to spathulate to long-triangular. Corolla stellate or rotate-stellate, white or purplishtinged to lavender, usually with an "eye" at the base of the lobes of a contrasting colour (yellow, green or dark purple-black), the lobes spreading or reflexed at anthesis. Stamens equal or very slightly unequal, the filaments equal, glabrous or more usually densely pubescent with tangled uniseriate weak-walled simple uniseriate trichomes, the anthers ellipsoid (sometimes slightly tapering in S. scabrum) and connivent, with distal pores that elongate to slits with drying and/or age. Ovary conical, glabrous or occasionally very minutely puberulent; style straight or curved and bent, usually pubescent with simple uniseriate trichomes in the lower half, only very slightly exserted from the anther cone; stigma minutely capitate to capitate or clavate. Fruit a globose or somewhat elongate juicy berry with thin pericarp, green, black, yellow or red-orange at maturity; fruiting pedicels spreading or deflexed; fruiting calyx lobes reflexed, appressed or accrescent at fruit maturity. Seeds flattened and tear-drop shaped, yellow or tan-brown. Chromosome number: n=12, 24, 36 (see section on Chromosomes, and individual species treatments). Distribution. A worldwide species group occurring on all continents except Antarctica, but with highest species diversity in South America and Africa.
Discussion. In the synonymy here, we have included all groups that are members of the clade as we define it, not only those containing Old World species; for more detailed discussion of morphology and group definition see Särkinen et al. (2015a). Solanum nigrum is the lectotype species of Solanum (Hitchcock and Green 1929) and thus, if this group were to be formally recognised at the infrageneric level at any given rank, it would necessarily be called [rank] Solanum (as recognised by Seithe 1962).
Members of the Morelloid clade are amongst the most widely collected of solanums, in part because are they are herbaceous, widespread and weedy. They are also amongst the most difficult to identify, due to their extreme vegetative plasticity (see Morphology above) and their lack of striking distinguishing characters. Combinations of characters are most useful for identification and we have included these in the species treatments as well as in the keys. Species are often most usefully identified based on geography (i.e. where they are found), but the large number of potentially invasive and introduced species means one must exercise caution if a species is not readily identifiable (taking into account variation, of course). The many specimens grown in the 19 th century in botanical gardens present special difficulties -these are not included here in species treatments or keys, except as type citations. Many morelloid species from the Americas were sent as seeds to European botanical gardens (e.g. S. americanum, S. chenopodioides, S. emulans Raf., S. nigrescens Martens & Galeotti) and, though cultivated, they did not escape and become part of the local floras of the regions. In order not to confuse users, we have limited our treatment here to include only native and a set of non-native introduced species that have become naturalised and persistent in the Old World.
The Morelloid clade suffers from two extreme sorts of taxonomic recognition issues. Firstly, in many parts of the world, especially in more recent floras, all taxa are treated as a single highly variable species (usually S. nigrum) and local endemic taxa are overlooked. Secondly and especially in Europe in the late 19 th and early 20 th century, many minor variants were described and then were transferred and recombined at different taxonomic levels, creating a confusing morass of names, many of which lack types. The latter is unfortunate because of the nomenclatural work entailed in sorting out the identities and types for these names, but the former is more serious, because endemic taxa have been overlooked and thus have possibly been placed at risk due to their being equated with widespread invasive weeds.
Artificial key to species of the Morelloid clade occurring in the Old World (Africa, Asia, Europe and Australasia including the Pacific) Description. Annual or short-lived erect to somewhat spreading perennial herbs, height not known, likely subwoody and branching at base. Stems spreading to decumbent, terete, sometimes recorded as greenish-violet (Afriastini 475), older stems yellowish-brown, with no prickle-like projections, not markedly hollow; new growth densely pubescent with simple, spreading, uniseriate, glandular or eglandular trichomes, the trichomes 6-8(-10)-celled, ca. 0.5 mm long, if glandular then with a terminal gland, sometimes drying with a yellowish-brown tinge. Sympodial units trifoliate to plurifoliate, the leaves not geminate. Leaves simple, (2-)5-12 cm long, (0.5-)1-3 cm wide, lanceolate to ovate, most commonly narrowly elliptic or broadly lanceolate, membranous, concolorous, smell not known; adaxial surface pubescent with simple, uniseriate, glandular or eglandular trichomes evenly and moderately spread along veins and lamina; abaxial surface similar but the pubescence denser along the veins; major veins 7-8 pairs; base cuneate to attenuate; margins entire or shallowly toothed, the teeth, if present, narrow and acute; apex acute to acuminate; petioles ca. 1 cm long, pubes- cent like the stems and leaves. Inflorescences 2-4 cm long, internodal, unbranched or furcate, with 5-10 flowers mostly clustered at the distal end of the rhachis, pubescent with simple uniseriate trichomes like those of the stems and leaves; peduncle 1.0-3.5 cm long, straight; pedicels 1.0-1.3 cm long, ca. 0.5 mm in diameter at base and apex, filiform, spreading, pubescent with simple uniseriate trichomes like the rest of the inflorescence, articulated at the base; pedicel scars mostly clustered at the distal end of the rhachis and overlapping, sometimes up to 1.5 mm apart in the distal half of the rhachis. Buds narrowly ellipsoid, the corolla soon exserted from the calyx tube. Flowers 5-merous, all perfect. Calyx tube 1-2 mm long, broadly conical, the lobes 0.5-1.0 mm long, ca. 1 mm wide, broadly deltate to triangular, tips acute, densely to moderately pubescent with simple uniseriate 6-8-celled trichomes. Corolla 9-12 mm in diameter, purple or violet, stellate, lobed 2/3 to 3/4 of the way to the base, the lobes 3-4.5 mm long, 1.5-2.0 mm wide, spreading or reflexed, densely papillate along the margins and on the tips. Stamens equal; filament tube < 0.2 mm long; free portion of the filaments ca. 1 mm long, densely pubescent adaxially with tangled simple uniseriate trichomes; anthers 2.8-4 mm long, ca. 1 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary rounded, glabrous; style 5-6 mm long, densely pubescent with tangled simple uniseriate trichomes in the basal half, exserted up to 2 mm from the anther cone; stigma minutely bilobed, the surfaces minutely papillate. Fruit a globose berry, 6-9 mm in diameter, black, the pericarp thin and matte; fruiting pedicels 1.2-1.3 cm long, ca. 0.5 mm in diameter at the base and apex, spreading or strongly deflexed, spaced (0-)0.5-1.5 mm apart, not falling with the berry, persistent on older inflorescences; fruiting calyx not accrescent, the tube less than 1 mm long, the lobes ca. 1 mm long, loosely appressed to the berry, not markedly reflexed. Seeds 20-50 per berry, 2.5-3.0 mm long, ca. 1 mm wide, flattened reniform, golden brown to brown, the surfaces minutely pitted, the testal cells small, rectangular to pentagonal in shape. Stone cells (0)2-4 per berry. Chromosome number not known.
Distribution ( Figure 6). Endemic to Indonesia and is found along the mountainous volcanic spine of Java, Bali and Lombok (Lesser Sunda Islands).
Ecology. Grows in montane habitats, in grassy areas along forest margins or in clearings; between 1,700 and 3,100 m elevation.
Preliminary conservation status (IUCN 2016). Solanum alpinum, although found over a relatively large geographical area, is never common and is known from a small number of collections. With a relatively small AOO of 64 km 2 (EN) and EOO of 18,806 km 2 (VU) and, in view of the scattered populations at isolated high elevations, we assign the species a preliminary conservation status of VU (Vulnerable; Table 7). Forests on these mountains are under threat from land conversion and fire associated with human use (van Steenis 2006). Discussion. Solanum alpinum is a plant of high elevations with both glandular and eglandular morphs. Glandular forms were named as S. viscidissimum, while in the same publication eglandular forms were named S. alpinum. As the two names have not been synonymised before (neither name was included in Backer and Bakhuisen van der Brink 1965 or in van Steenis 2006), we have chosen to use S. alpinum over S. viscidissimum because the name is more generic and appropriate for the distribution of the species. It can be distinguished from S. americanum and S. nigrum, both of which also occur in Indonesia, by its larger usually violet flowers on long pedunculate inflorescences. Anthers of S. alpinum are 2.8-3.8(-4) mm long, while those of S. americanum are minute (ca. 1.5 mm) and those of S. nigrum ca. 2 mm long. The leaves are usually narrower and longer (more lanceolate) than either of those two species, but two Horsfield collections with smaller, rounder leaves are included here based on anther length and flower size, so variability could be greater than we have seen to date.
The plant illustrated as "Solanum nigrum" in van Steenis (2006: plate 51) is likely to be S. alpinum; the excellent illustration has the narrow leaves, long pedicels and large flowers characteristic of that species. The dismissal of it as a probable introduction has been the fate of all of the more narrowly distributed members of this group. The distribution of S. alpinum along the volcanic chain of Java above 2,000 m elevation is typical of other members of this rich flora that are found in areas created and influenced by fire resulting from volcanism and subsequent open habitat and grassland creation (as described in van Steenis 2006). Solanum alpinum is likely to also occur in the "tjemara forests" (sensu van Steenis 2006) dominated by Casuarina junghuhniana Miq. (Casuarinaceae). Further fieldwork and more accurately geolocated collections are needed to ascertain the distribution and habitat preferences of S. alpinum.
A single collection of Zollinger was cited for each of S. alpinum ("Herb. N. 2255") and S. viscidissimum ("Herb. N. 2514"), but no herbarium was cited; we have lectotypified S. alpinum with the P (P00368905) duplicate of Zollinger 2255, because it has a label with the protologue locality. We have selected the G-DC (G00357866) sheet of Zollinger 2514 as the lectotype for S. viscidissimum as the best preserved of the duplicates we have seen.

Solanum americanum
Distribution (Figure 9). Globally distributed weed found across tropical and subtropical areas; probably native to the Americas, but there is little evidence for its origin or introduction.
Ecology. Grows in disturbed habitats and associated with human activities in tropical moist to dry areas, in dry areas often found growing in full shade close to water sources; between sea level and 2,000 (-2,500) m elevation.
Common names. American Samoa: magalo; Australia: glossy nightshade (Symon 1981); Benin: odu, ogomo, feibii (Essou and Hermans 2006); China: shao hua long kui, guang zhi mu long kui (as S. merrillianum) (Zhang et al. 1994 Uses. In all parts of its range, the leaves of S. americanum are used as spinach and the ripe berries are eaten, either raw or cooked. Preliminary conservation status (IUCN 2016). Solanum americanum is an extremely widespread cosmopolitan weed and can be assessed as LC (Least Concern; Table 7).
Discussion. Solanum americanum is a diploid species that can be easily recognised by its shiny black fruits on spreading pedicels with strongly reflexed calyx lobes (to parallel with the pedicel) that are somewhat papillate abaxially. In fruit, the pedicels remain on the plant after fruits fully mature and drop off, leaving behind a distinct group of tightly clustered spreading pedicels with reflexed calyx lobes; this character is easily visible in many herbarium specimens. In flower, S. americanum has tiny, almost globose anthers 0.8-1.5 mm long borne on short filaments. It can be distinguished from S. opacum, which also has tiny anthers of the same size, in its shorter filaments relative to anther size and in its deltate calyx lobes with rounded tips. Solanum opacum has longer filaments relative to anther size, long-triangular calyx lobes and, in fruit, the calyx lobes are appressed to the base of the berry. Three other morelloids with such small anthers can be difficult to distinguish from S. americanum and are often confused with it in herbaria. Solanum emulans Raf. does not occur in the Old World (except sometimes in old botanical garden collections, see discussion of the typification of S. patulum and S. dillenii below; it is a species of the north-eastern United States and Canada) has matte berries and longer calyx lobes. Solanum nitidibaccatum also has extremely small anthers, but can be easily distinguished by its glandular pubescence and accrescent calyx in fruit. Solanum opacum is the third morelloid with tiny anthers and the most difficult to distinguish from S. americanum in the Old World. Solanum americanum and S. opacum co-occur across the Pacific and distinguishing individual specimens can be difficult, but the shiny fruits (versus matte in S. opacum) and persistent pedicels with strongly reflexed calyx lobes are good characters by which to recognise S. americanum.
In southeast Asia and China, S. americanum is at least partially sympatric with S. nigrum (see discussion of S. nigrum). The species can be distinguished by anther size (0.8-1.5 mm versus ca. 2-2.5 mm) and by inflorescence morphology; S. americanum usually has few flowers that are tightly congested in the distal part of the inflorescence, while S. nigrum usually has more flowers that are more spaced out along the inflorescence rhachis, although young inflorescences of S. nigrum can appear sub-umbellate. In fruit, the strongly reflexed calyx lobes of S. americanum are distinctive and the seeds are smaller than those of the hexaploid S. nigrum (ca. 1 mm versus ca. 2 mm long). Solanum merrillianum was recognised as a distinct species in the Flora of China (Zhang et al. 1994), but variation described fits within the observed variation of S. americanum after studies of the species across its global range. Specimens described as S. merrillianum show branching inflorescences in some individuals with generally larger number of flowers per inflorescence than seen in S. americanum, but the larger inflorescences may be due to pre-domestication and/or selection of the species in China and Taiwan, where fruits of S. americanum are commonly eaten.
Solanum americanum exhibits the highest infraspecific genetic diversity compared to polyploids (Dehmer and Hammer 2004). Based on its distribution, molecular and crossing experiments, it is believed to be the diploid parent of the two hexaploids S. nigrum and S. scabrum (Edmonds 1979a, Ganapathi and Rao 1987a, 1987b). There are a relatively few differences between the two species in SSR (Dehmer 2001), AFLP (Dehmer and Hammer 2004), RAPD (Poczai et al. 2010), ISSR and SCoT  and intron-targeting markers (Poczai et al. 2014) and a number of additive bands could be counted between S. americanum and the two hexaploids indicating their parental relationships. Solanum americanum is also the putative parent of the tetraploid S. villosum .
The taxonomic status and relationship of S. americanum to S. nodiflorum was studied by Manoko et al. (2007). Solanum nodiflorum has been considered as a distinct taxon by some (e.g. Henderson 1974) while a synonym or infraspecific taxon of S. americanum by others (e.g. Edmonds 1971;D'Arcy 1974a, b;Symon 1981). Manoko et al. (2007) used AFLP data to study the relationship between the two taxa, but used different taxon concepts than we adopt here, in part because their examination of type specimens was limited. Based on detailed study of the voucher material used, it is clear that the taxon referred to as S. nodiflorum in Manoko et al. (2007) refers to what is considered S. americanum in this treatment, while material referred to as S. americanum represents S. nigrescens M.Martens & Galeotti, a species endemic to the New World. Such confusion is easy in this complex group when studying only a portion of species and their ranges even though type material was consulted in the original paper by Manoko et al. (2007). The taxon referred to as Solanum sp. from Brazil in Manoko et al. (2007) also refers to S. americanum as treated here, but represents a morphological variation mainly observed within the New World and was hence difficult to interpret with limited sampling in previous studies. The re-examination of the study results by Manoko et al. (2007) in the light of the new identifications, highlights the fact that clear population structure can be observed within S. americanum as circumscribed here, where populations from Brazil show high genetic divergence from the rest of the World, including northern South American material.
The results described above, based on AFLP markers, should be tested with modern population genetic tools such as functional markers (Poczai et al. 2013) or genotyping-by-sequencing (GBS) and phylogenetic analysis. Species-level phylogenetic studies with multiple accessions of all species would also be useful in confirming the monophyly of the highly variable and widespread S. americanum in the context of other species of the Morelloid clade. Edmonds (2012) incorrectly designated as the lectotype of S. nigrum var. patulum L. a specimen in the Dillenian herbarium at OXF. This typification is in conflict with the protologue (see McNeill et al. 2012, Art. 9.19) because the specimens themselves are not original material for this name. Linnaeus never saw Dillenius's herbarium (Jarvis 2007), but based his name entirely on the plates from Hortus Elthamensis (Dillenius 1732). We have therefore re-lectotypified this name based on original material and designated the specimen chosen by Edmonds as the epitype.
The identity of the species depicted in plate 355 (Dillenius 1732) has been the subject of much speculation. Thellung (1927) studied material in Dillenius' herbarium at OXF in an attempt to come to grips with the identity of S. dillenii (see below) and made careful annotations on specimens associated with plate 355. Material stored under plate 355 is mixed; some specimens are of the North American endemic S. emulans Raf. with 9-11 stone cells, calyx lobes appressed to the berry and matte fruit texture and others are of S. americanum with no or up to 4 stone cells, strongly reflexed calyx lobes in fruit and shiny mature berries. Thellung (1927) associated the name S. dillenii with the Dillenian specimens of the North American native S. emulans, but did not realise that there were two taxa involved in the material stored under plate 355. Polgár (1939) re-described S. dillenii, confining it to his original circumscription (Polgár 1926) and equating it with S. nodiflorum and coined a new epithet, S. dillenianum Polg. for the North American material in the Dillenian herbarium that had been called S. nigrum var. dillenii by Gray (1878). We have epitypified the name S. nigrum var. patulum to conform with current usage because, in our view, the plate is unambiguously of a plant of S. americanum with small flowers, black fruit and sepals that are strongly reflexed in fruit.
Solanum papilionaceum was almost certainly described from living material only. Dumont de Courset (1802: 135) cited no specimens and gave no other provenance than "Cette morelle, qui m'a été envoye en graines du Jardin. nat". Searches in Paris have revealed no authentic original material, so we have selected a neotype that is a specimen dated after the description that was cultivated in Paris (P00582223). The specimen matches the description, which is of a plant with small flowers in umbelliform inflorescences and fruits like "cassis" (blackcurrants).
The specimens in Zuccagni's herbarium in Florence were consumed by fire, making the designation of a neotype for S. strictum Zucc. necessary. The specimen we have selected is dated later than the description, but is labelled as "strictum Zucc." and is from Italy in cultivation (G00144215); it was used by Dunal in his Prodromus treatment as S. strictum (Dunal 1852).
The identity of Schultes's (1814) name S. dillenii has a complex history. Schultes (1814) coined a replacement name because the epithet "patulum" had been used at the species rank by Persoon (1805: 223) for the Peruvian taxon now known as S. ruizii S.Knapp (see Knapp 1989Knapp , 2013. He did not realise that Roth (1800) had already recombined Linnaeus' S. nigrum var. patulum (see above) at the specific rank, basing his description entirely on Hortus Elthamensis plate 355 (Dillenius 1732). In his protologue, Schultes refers to a collection by Kitaibel from Hungary ("das ich vor mir habe" [which I have before me]) and the illustration in Hortus Elthamensis (Dillenius 1732) and describes a plant with small flowers and fruits borne on erect pedicels. Polgár (1926) examined the specimen in Kitaibel's herbarium ("A IX Fasc. 102") labelled "Solanum nigrum an patulum, Esse patulum affirmat Willdenow. In silvis Matrae" and equated the specimen with the American species he called S. nodiflorum Jacq. and suggested it was not native to Hungary, but rather from a botanic garden. This sheet (Herb. Kit. Fasc. IX,No. 102) in BP is a tangled mixture of two elements (see Poczai et al. 2009). One stem has small flowers in sub-umbellate inflorescences and matches the protologue description (but has no fruit) and the other stem has larger flowers in elongate racemose inflorescences and was identified by Poczai et al (2009) as S. scabrum. It is quite possible that there was considerable mix-up with the labelling of plants in Kitaibel's herbarium; a specimen at BP (Herb. Kit. Fasc. IX, No. 101), exactly matching the small-flowered stem of Herb. Kitaibel fasc. IX, No. 102, is labelled "Solanum nigrum β patulum" in Kitaibel's hand and "ex horto" in another hand. It is possible that the large-flowered plants collected in Mátra (which we identify as S. nigrum) were mixed with small-flowered plants from cultivation and, in distributing duplicates, confusion ensued. As Schultes (1814) cited a specimen (see McNeill et al. 2012, Art. 9.12), we have lectotypified S. dillenii with the only sheet in the Kitaibel herbarium (BP) that bears the locality cited in Schultes's (1814) protologue, but limit our typification to the stem with small flowers only. A sheet in B-W [B-W 04364-03] of Kitaibel's with a label in his hand "161/Solanum nigrum an patulum ?/In sylvis Hungaria" is certainly a duplicate; we cannot be sure this is the sheet Schultes had in his possession, since the locality is not exactly the same as that in the protologue and it does not have fruit. The BP sheet (fasc. IX No. 101) is also possibly a duplicate; it does have berries borne on erect pedicels. Gray (1878) used Schultes's epithet at the infraspecific rank (as S. nigrum L. var. dillenii (Schult.) A.Gray) for plants from north-eastern North America now known as S. emulans Raf.
In describing S. microspermum, Dunal (1816) used an unpublished name by L'Heritier and cited a specimen and his own unpublished illustration, now held in MPU. We have selected the specimen in G-DC that comes from "herb. Thibaud" and is annotated by Dunal as the lectotype. The online catalogue at G indicates the collector of this sheet as "L'Héritier de Brutelle".
Although the protologue of S. erythrocarpon (Meyer 1818) indicates the fruits are red ("Baccae pendulae, pisi minoris magnitudine, lutescenti-rubrae, nitidae"), the specimen in GOET (GOET003505) that represents original material for this name (here selected as the lectotype) matches S. americanum in all other respects. D'Arcy (1974a: 735) cited as "type" a specimen in P as "Type: Herb. Rich. (P)" with a footnote stating that the sheet has two labels, one with "Isle de France" in Dunal's hand and the other indicating it is from Herb. Richard. Since the protologue does not mention Isle de France and Dunal had nothing to do with the description of this name, this unintentional lectotypification is in conflict with the protologue, in which the locality is "insulae Cubae" and Richard is mentioned. We therefore supersede it and designate a specimen in P (P00370899) that matches the protologue in being from Cuba and originally from Herb. Richard as the lectotype for S. indecorum. Sendtner (1846) described his var. aguaraquiya referring to Piso's (1648: 55) pre-Linnaean name "Aguara-quiya" and citing un-numbered collections of Sellow and one Martius collection with a number and locality we have here selected as the lectotype. The Sellow collections associated with this name (BR [BR0000005538058], K, W [W0004136]) have large anthers and represent S. chenopodioides; they have neither numbers nor localities. The specimen selected as lectotype here (Martius 1225, M-0171809) contains detail of collection locality cited in the protologue and is hence the best material. D'Arcy (1974a) lectotypified both S. amarantoides (Gaudichaud 552) and S. nodiflorum var. acuminatum (Vauthier 537) by stating "type" and a single herbarium, "P". In the case of S. amarantoides, two specimens are found in P; we have selected that which has a label with Dunal's handwriting in a second step lectotypification (P00319574). For S. nodiflorum var. acuminatum, however, D'Arcy (1974a) cited "P, ex Herb. Drake", indicating a single specimen. Unfortunately, this specimen (P00319615) is not the duplicate of Vauthier 537 with Dunal's label (that with the annotation from Dunal is P00315614), but must be accepted as the lectotype nevertheless.
In describing S. minutibaccatum, Bitter (1912a) cited a single Buchtien collection (Buchtien 1443), but no herbarium. We have selected the sheet in US (US00027684) as the lectotype because it is the best preserved of the duplicates we have seen.
Solanum calvum was described using "Palmer 60 p. pte." (Bitter 1913b) with a single herbarium cited ("herb. Upsal."). Edward Palmer began his number series again on every collecting trip (McVaugh 1956), but the collection number in question here refers to plants collected on Guadalupe Island (Baja California) in 1875. Other duplicates of Palmer 60 (another sheet at UPS, MO [MO-158569]) are part of type material of S. profundeincisum Bitter, a synonym of Solanum douglasii Dunal from Mexico and the south-western United States, while others are of material of S. nitidibaccatum (BM001017193 and MO-158570). We exclude these as types of S. calvum and urge caution when interpreting other duplicates of Palmer 60.
The protologue of S. nigrum var. pauciflorum (Liou 1935) cited three specimens from Hainan Island; Chen 1, Wang 2 and Lau 209, all perhaps from LU, although no herbarium was cited. We select here the more widely distributed Lau 209 with the BM sheet (BM000942311) as lectotype for this name.

Solanum chenopodioides
Distribution ( Figure 12). Thought to be native to southern South America (see Barboza et al. 2013), but introduced globally in temperate and subtropical areas.
Ecology. Grows in humid, disturbed areas between rocks, along water sources and roads and in cultivated lands, common in areas with human disturbance; between sea level and 1,900 (-2,500) m elevation.
Preliminary conservation status (IUCN 2016). Solanum chenopodioides is an extremely widespread cosmopolitan weed and can be assessed as LC (Least Concern; Table 7). When only the putatively native South American distribution is considered, S. chenopodioides still has a very large EOO of 2,279,138 km 2 and remains LC.
Discussion. Solanum chenopodioides can be distinguished from most of the other morelloids occurring in the Old World based on its narrowly lanceolate leaves with grey indumentum, inflorescences with ca. 3-7 flowers tightly congested near the tip of the peduncle, the stellate corollas that are deeply lobed to the base and usually with a dark purple or black central star and anthers that are usually more than 2 mm and up to 2.8 mm long. In fruit, the pedicels and proximal portion of the peduncle are strongly reflexed and the berries are not at all shiny. Solanum retroflexum has similar matte black berries, but has rhomboid leaves, less deeply divided corollas, shorter anthers and the calyx lobes are strongly reflexed in fruit. Solanum chenopodioides could also potentially be confused with the more common S. nigrum, especially in Europe, but differs from that species in its terete stems, matte black fruits on short strongly reflexed pedicels and its smaller seeds (1.2 mm long versus 2 mm long).
Solanum chenopodioides has a scattered distribution in the Old World, but it seems to be spreading, perhaps related to climate change and/or increased habitat alteration (Martínez Labarga et al. 2017).
This diploid species possibly contributed its genome to the tetraploid S. retroflexum and hexaploid S. opacum. Jacoby and Labuschagne (2006) reported that crosses made between S. chenopodioides and S. retroflexum were much more successful than between S. americanum and S. retroflexum. This relationship was also confirmed by arbitraryamplified dominant markers (Jacoby et al. 2003; and by whole genome DArT analysis by van der Walt et al. (2008). Morton (1976) thought the locality on the type specimen of S. chenopodioides Lam. as "Mauritius" was in error, because the species was a New World taxon in his concept. Morton suggested that the Commerson material on which the name was based was actually from Argentina, but that the localities had been mixed up. This may be true, because there is much material collected by Commerson from Argentina and Uruguay, but S. chenopodioides also occurs on Mauritius as an introduced weed and we are hence reluctant to suggest the locality is an error.
In the protologue (Roemer and Schultes 1819: 593) of S. besseri, both the name and description are attributed to Johann Anton Weinmann ("Weinm. in litt.") but no specimens or collections are cited. The description is of a plant with subumbellate inflorescences, black fruits and that comes from America, meaning that, in the absence of a type specimen, it is difficult to determine the identity of this species. Later Weinmann (1824) published a list of plants from St. Petersburg in which he lists "S. besserianum" (a nomen nudum with no description) that is probably the same plant, stating it is from "America" and equating it with "S. cestrifolium Jacq.?" (see Doubtful names). Dunal (1852) made a detailed description of S. besseri and put S. americanum in synonymy with it. His description was based on a specimen he saw in "herb. DC" and living plants. In the absence of any original material for this name, we neotypify it here with the specimen in G-DC (G00144198) used by Dunal (1852) and labelled "Solanum besseri" in his hand. The specimen matches his detailed description exactly and it is not in conflict with the original description (Roemer and Schultes 1819). We do this in order to stabilise the identity of this name so it does not further disrupt names in this group (e.g. see discussions of S. memphiticum and S. villosum).
In the protologue of S. isabellei, Dunal (1852) cited specimens in G-DC (Isabelle s.n.) and P (Gay s.n., 1828); we have selected the collection Isabelle s.n. (G00145645) as the lectotype because it is well represented by duplicates in other herbaria. He cited various sheets of plants collected by Philibert Commerson in Uruguay and Argentina as material for his new names S. chenopodiifolium, S. gracile and S. gracile var. microphyllum. There are many Commerson collections corresponding to S. chenopodioides in P, none of which we are treating as strict duplicates; although they have similar morphologies, they all have slightly different collecting localities and labels. Conrad V. Morton (1976) lectotypified S. gracile var. microphyllum by citing his photograph (Morton neg. 8207) of specimens in P and we have matched this to the individual sheet and add the barcode here as a second step lectotypification. We have selected another of the Commerson sheets in P that is annotated by Dunal as "S. chenopodiifolium" as the lectotype of that name.
Solanum gracile was incorrectly typified by D'Arcy (1974a) on "Hort. Monsp. 1831 (MPU)", but Dunal did not cite herbarium material from Montpellier, he only cited living material from there ("v.v.") along with herbarium material from G-DC and P ("v.s. in h. DC h. Mus Paris. et v.v."). Any herbarium material prepared from such living specimens would be a neotype, but that is inappropriate while syntypes still exist. Henderson (1974) cited as lectotype for S. gracile a sheet in G-DC without citing a collector, but he did cite a microfiche number (IDC 800-61.2063:III.7) that corresponds to Gaudichaud 520, the material cited in the protologue. His lectotypifcation is effective, because he cited a single collection in a single herbarium (G-DC, G003144391); duplicates in G and P are isolectotypes. Morton (1976) later superfluously lectotypified S. gracile with Commerson material at P, citing his photograph (Morton neg. 8206); this specimen (P00384083) is not a type, although it was cited as the lectotype by Barboza et al. (2013).

Solanum furcatum
Distribution (Figure 15). Native to Pacific coastal South America and locally introduced and naturalised in the states of Victoria and Tasmania in Australia and in the western United States of America (California and Oregon, see Bohs in press); Although the disjunct distribution of the species appears peculiar, other taxa native to the Pacific coast of South America have become established in similar areas with Mediterranean climates (e.g. Nicotiana acuminata (Graham) Hook.). Ecology. Open places and disturbed areas, along roadsides and field margins; between sea level and 3,000 m elevation in its native range, in Australia collected in coastal habitats along the foreshore or along creeks near sea level.
Common names. Australia: broad nightshade (Walsh and Entwisle 1999). Uses. None recorded for Old World collections. Preliminary conservation status (IUCN 2016). Solanum furcatum, while only rarely encountered in the Old World, is common in its native range in Chile ( Barboza et al. 2013;Särkinen et al. 2015b) and can be assessed as LC (Least Concern; Table 7) on a worldwide basis. In its native range in South America, it has an EOO of 1,809,315 km 2 and is not of conservation concern.
Discussion. Solanum furcatum can be distinguished from all other Old World species based on its branched inflorescences, anthers 2.3-3.3 mm long and flowers where styles are exserted up to 3.0 mm beyond anthers. It has been sparingly introduced into areas of Mediterranean habitat (e.g. Australia and California) but appears not to spread. It is potentially confusable with S. nigrum, but is distinguished from it by the characters mentioned above and by its 2-13 stone cells per berry. Its subglobose buds are also distinct from the more ellipsoid buds of S. nigrum and S. villosum, but this character can be hard to see in herbarium specimens.
The name S. douglasii Dunal has been misapplied to some specimens of S. furcatum in Australia (e.g. Symon 1981;Walsh and Entwisle 1999). Careful assessment of the specimens cited in these publications and material labelled as S. douglasii confirms that the specimens from Victoria represent S. furcatum. Solanum douglasii is native to Mexico and the south-western United States of America and is known only from cultivation in the Old World. Colla (1835) described S. deltoideum from material grown in Italy from seeds sent by C. Bertero from Chile as "Solanum scabrum". Of the two specimens from Colla's herbarium in TO, only one is labelled as originally identified as "S. scabrum" and this is the sheet we select as the lectotype of S. deltoideum.
The infraspecific taxa of S. furcatum described by Nees van Esenbeck (1843) were all based on specimens collected by F. Meyen (fide protologue) during his 1830-1832 voyage on the Princess Louise to Chile and Peru; we have found no duplicates of these and so have chosen not to lectotypify these names until further in-depth searches have been conducted. These may belong to S. arequipense Bitter described from Arequipa which was previously considered as synonym of S. furcatum but is distinct based on morphology, ecology and molecular evidence.
Solanum rancaguense was lectotypified by Edmonds (1972) by citation of a P specimen of Bertero 633 as "holotype", but because there are several sheets of this collection number preserved in P, this is correctable to lectotype and we select a particular sheet (P00384088) of the five there as a second step lectotype.
We have selected lectotypes in SGO for the taxa described by Philippi here considered synonyms of S. furcatum following the advice of Smith and Figueiredo (2011). None of the protologues specifies herbaria and, although Philippi worked in Chile, we have followed McNeill (2014)   Description. Annual to short-lived, mostly prostrate perennial herbs to 5-20(-150) cm high, branches ascending from woody tap-root. Stems decumbent to ascending, terete or very slightly winged from decurrent leaf bases, green or straw coloured, older stems not appearing spinescent, yellowish-brown, not markedly hollow; new growth moderately pubescent with simple, antrorse, uniseriate, eglandular trichomes, these 5-7-celled, 0.5-0.8 mm long, white. Sympodial units difoliate, the leaves not geminate. Leaves simple, 1.5-5.0(-6.0) cm long, 0.7-1.8 cm wide, narrowly elliptic to lanceolate, narrowing gradually to the base, concolorous, without smell; adaxial surface sparsely and evenly pubescent with simple, uniseriate trichomes like those on stem; abaxial surface with a few evenly scattered trichomes like those of the adaxial surface; major veins 5-7 pairs; base long-attenuate, decurrent on the petiole; margins entire to sinuate; apex acute to acuminate, the tip slightly rounded; petioles absent, the laminar tissue extending to the junction of leaf and stem. Inflorescences 0.5-2.2 cm long, opposite the leaves, simple, sub-umbelliform to shortly racemose, with 1-5 flowers clustered in the distal portion, sparsely pubescent with antrorse simple uniseriate trichomes like those of the stems; peduncle 0.4-1.8 cm long, straight; pedicels 0.7-1.6 cm long, ca. 0.5 mm in diameter at the base and apex, stout and spreading, articulated at the base; pedicel scars clustered at the tip of the inflorescence rhachis and overlapping, occasionally the basal scar 1-2.5 mm distant. Buds ellipsoid, the corolla halfway exserted from the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx tube 2.0-3.0 mm long, conical, the lobes 0.8-1.2 mm long, 0.8-1.2 mm wide,  linear-oblong, tips rounded, densely pubescent with trichomes like those of the stems and pedicels.  mm in diameter, deep purple to pale violet, stellate, lobed 3/4 of the way to the base, the lobes 4.5-8 mm long, 2-3 mm wide, spreading to reflexed, densely papillate abaxially, the papillae denser along margins and tips. Stamens equal; filament tube ca. 0.5 mm long; free portion of the filaments ca. 0.5-1.0 mm long, adaxially densely pubescent with tangled simple uniseriate trichomes; anthers 2.3-2.8 mm long, 0.6-0.9 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary rounded, glabrous; style 4.5-5.5 mm long, densely pubescent with simple trichomes in the basal 1/3, exserted ca. 1 mm beyond anther cone; stigma large-capitate, the surfaces minutely papillose. Fruit a globose berry, 5-6 mm in diameter (immature?), mature berry colour not known, the pericarp thin and matte or somewhat shiny; fruiting pedicels 0.7-1.6 cm long, 0.5 cm in diameter at the base and 1.0-1.2 mm at the apex, stout with slight curving at the base, reflexed, dropping with mature fruits, not persistent; fruiting calyx not accrescent, the tube ca. 1 mm long, the lobes 1-1.5 mm long, appressed to the berry. Seeds (10-)20-35 per berry, ca. 1.8-2.0 mm long, ca. 1.5 mm wide, not markedly flattened, tear-drop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells pentagonal to rectangular in outline. Stone cells 2 per berry, ca. 0.6 mm in diameter. Chromosome number: not known.

Solanum hirtulum
Distribution (Figure 18). Endemic to the high mountains of Ethiopia on the western side of the Rift Valley.
Ecology. Grows in open grassy areas, arable land, along river banks, in forest and along roadsides; between 2,200 and 3,500 m elevation.
Common names. None recorded.
Uses. None recorded. Preliminary conservation status (IUCN 2016). Solanum hirtulum is a countryrestricted endemic with AOO of 48 km 2 (EN) and EOO of 49,487 km 2 (LC). The species is known from a small number of records, and it could be that the lack of collections reflects small population sizes and/or local rarity. From the EOO measure, it would be assessed as LC (Least Concern), but since it is a single-country endemic, it merits some attention and we assign the species as NT (Near Threatened; Table 7). The high mountains where it grows are at threat from grazing and human disturbance, but S. hirtulum, like other members of this group, is a species of open, disturbed areas. The Simien Mountains have protected status as both a World Heritage Site and as a National Park in Ethiopia.
Discussion. Solanum hirtulum is a distinctive prostrate, creeping herb with narrow lanceolate attenuate leaves with strigose, somewhat antrorse pubescence. The flowers are larger than others in the group in Africa and appear to always be purple or "blue"; this, however, must be taken with caution given the high degree of flower colour polymorphism in other species. The inflorescences are usually few-flowered with tightly spaced flowers at the very tip. Solanum hirtulum is similar to S. memphiticum in having black berries with a somewhat accrescent calyx, but the flowers of S. memphiticum are always smaller, usually white and more delicate (see description of S. memphiticum). The leaf bases in S. hirtulum are strongly attenuate and decurrent on to the stem.
Solanum hirtulum is a plant of Afromontane vegetation (sensu White 1981White , 1983White , 1993. Linder (Linder et al. 2005;Linder 2014) showed that this vegetation type (as "Tropic-montane") was not necessarily a distinct unit across Africa, but instead was locally distinct based on high turnover in particular mountain blocks. Most clades from these forest types were Miocene in age (Linder 2014). For Ethiopia, Friis et al.
(2010) further characterised this vegetation as "moist evergreen Afromontane forest", with additional complexity added by the grasslands that are characteristic of the seral stages of forest regrowth in these areas. This forest type is only intact in limited areas (Friis et al. 2010); these are the forests where wild coffee grows and are areas of high endemism in the Ethiopian flora (Vivero et al. 2006). It is likely that S. hirtulum also occurs at the lower levels of Afroalpine vegetation (sensu Friis et al. 2010), in grasslands at forest edges. The type of S. hirtulum was collected from the Simien Mountains, the most important hotspot of endemism for Afroalpine and Afromontane species (Vivero et al. 2006).
The type number of S. hirtulum (Schimper 977) is also that for a plant collected in 1837 in Saudi Arabia (the type of Seddera intermedia Hochst., Convolvulaceae, see http://apps.kew.org/herbcat/getImage.do?imageBarcode=K000852498). He clearly reused numbers for his Ethiopian plants. Solanum monactinanthum is here placed in synonymy based on the description and following Edmonds (2006a)   ly angled, green, older stems green or straw colour, not markedly hollow; new growth densely viscid-pubescent with simple, spreading, uniseriate, mixed glandular and eglandular trichomes, these 3-10-celled, 0.5-2 mm long, with a terminal single-celled gland if glandular; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, (1.5-)2-9 cm long, (0.8-)1.2-5.5 cm wide, elliptic to ovate and widest in the basal third, membranous, concolorous, foul-smelling when crushed; adaxial surfaces moderately viscid-pubescent with a mixture of glandular and eglandular simple uniseriate trichomes 0.5-2 mm long like those of the stems, these denser along the veins; abaxial surfaces densely viscid-pubescent with similar glandular and eglandular simple uniseriate trichomes, these evenly distributed on veins and lamina; base acute, then attenuate and decurrent on to the petiole; margins entire or more often irregularly toothed, the teeth 2-4 mm long, acute; apex acute to acuminate, the tip often blunt and usually somewhat rounded; petioles 0.5-1.5 cm long, winged from the decurrent leaf base. Inflorescences 1-2.5(-3) cm long, internodal, simple, umbelliform to sub-umbelliform, with (2-) 3-5(-8) flowers clustered at the tip, densely viscid-pubescent with mixed glandular and eglandular simple uniseriate trichomes like those of the stems; peduncle 0.9-2(-2.3) cm long, straight; pedicels 7-9 mm long, ca. 0.5 mm in diameter at the base, 0.5-0.8 mm in diameter at the apex, spreading, densely to moderately viscidpubescent like the inflorescence axis, articulated at the base; pedicel scars clustered at the tip of the inflorescence, the scar from the basal flower spaced 1-2 mm from the rest. Buds globose to ovoid, the corolla exserted more than halfway from the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx tube 1-2.5 mm long, deeply conical, the lobes 1-1.5(-2) mm long, 0.5-0.8 mm wide, long-triangular, tips rounded, densely viscid-pubescent with mixed glandular and eglandular simple uniseriate trichomes to ca. 0.5 mm long. Corolla (8-)10-12 mm in diameter, white, rotate-stellate to stellate, lobed ca. 2/3 of the way to the base, the lobes 4-5 mm long, 3-4 mm wide, spreading or reflexed at anthesis, minutely pubescent-papillate abaxially with simple eglandular trichomes ca. 0.2 mm long, these white when dry. Stamens equal; filament tube minute; free portion of the filaments 0.5-1 mm long, glabrous or occasionally with a few tangled simple uniseriate trichomes adaxially; anthers (2-)2.5-3 mm long, 0.75-1 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style 4-6 mm long, minutely puberulent in the lower 1/4, merely papillate in plants with glabrous filaments, exserted ca. half the length of the anthers; stigma capitate-globose, bright green in live plants, the surface minutely papillate. Fruit a globose berry, 7-10 mm in diameter, black when ripe, the pericarp thin, matte and somewhat translucent; fruiting pedicels 0.8-0.9 cm long, ca. 0.75 mm in diameter at the base and to ca. 2 mm at the apex, somewhat woody, deflexed to spreading (often appearing like spokes of a wheel), dropping off with mature fruits, not persistent; fruiting calyx somewhat accrescent, the tube 2.5-3 mm long, the lobes 2.5-4 mm long, ca. 1.5 mm wide, somewhat spathulate, appressed to spreading, covering ca. 1/2 of the berry. Seeds 10-30 per berry, 1.5-2.5 mm long, 1.5-2 mm wide, flattened and tear-drop shaped with a subapical hilum, pale brown, the surfaces minutely pitted, the testal cells more or less pentagonal with some sinuate margins. Stone cells 2 per berry, 0.3-0.7 mm in diameter, usually borne near the base of the berry. Chromosome number: 2n=6x=72 (Bhiravamurty and Rethy 1983;Olet et al. 2015).
Distribution ( Figure 21). Distributed from the Arabian Peninsula (Saudia Arabia and Yemen) to Egypt and south in eastern Africa to Kenya and Tanzania, we have only seen a single collection from eastern Democratic Republic of the Congo.
Ecology. Grows in open areas and along streams in forests and dry areas, also cultivated in eastern Africa; from 800 to 3,000 (-3,500) m elevation.
Uses. In eastern Africa, leaves are eaten as spinach and berries are said to be edible. Preliminary conservation status (IUCN 2016). Solanum memphiticum is a widespread species with AOO of 320 km 2 (EN) and EOO of 4,489,278 km 2 (LC); considering the weedy nature of the species and the large EOO, we suggest a preliminary status of LC (Least Concern; Table 7) for the species. Like other members of the group, it is a species of open, disturbed areas, but is less common than S. tarderemotum or S. villosum in eastern Africa.

Discussion.
Solanum memphiticum was long confused with S. villosum; both are similarly villous plants with toothed leaves that are sometimes pubescent with glandular trichomes. Edmonds (2007) clarified not only the differences between the two species, but also the identity and correct name for S. memphiticum. The species can be easily distinguished in fruit; S. villosum has characteristic red-orange (or yellow) berries with strongly reflexed calyx lobes, while S. memphiticum has green or black berries with the calyx lobes somewhat accrescent and covering at least a third of the berry. Fruiting pedicels of S. memphiticum are typically spreading and, in live plants, form a small bicycle spoke-shaped structure, while those of S. villosum are deflexed. Live plants of the two species are easy to distinguish: the leaves (glandular trichomes) of S. memphiticum have a strong foetid odour of rotting meat that is markedly different from the slightly pleasant odour of S. villosum. In flower, S. memphiticum can be distinguished by its rotate-stellate corolla with small lobes that are strongly reflexed in flower and calyx lobes that extend beyond the corolla sinuses in open flowers. The flowers of S. memphiticum are delicate and only last a short time as compared to other species (the corolla bruises easily). Leaves of S. memphiticum are generally longer and thinner than those of S. villosum and the base is more decurrent on to the petiole so the free part of the petiole in S. memphiticum is much shorter than in S. villosum.
The parental origin of the tetraploid species has not been investigated in detail. Jaeger (1985) suggested that S. memphiticum might be part of a more broadly circumscribed S. villosum, which included a wide range of fruit colours. Manoko (2007) showed that S. memphiticum (as S. grossedentatum) does not group closely with S. villosum based on AFLP data but forms a distinct group related to accessions identified as S. tarderemotum, S. chenopodioides, S. nitidibaccatum (as S. physalifolium) and S. tweedianum. Further molecular work, based on sequence data, will be needed to understand the relationships and parental origins of S. memphiticum, but possible diploid parents could be the morphologically closely related S. sarrachoides or S. nitidibaccatum that both occur in the Old World. Both of these species are glandular and have an enlarged calyx in the fruit, characters shared with S. memphiticum.
Distribution (Figure 24). Widespread species native to Eurasia (western Europe to Japan), northern Africa and Australia, sporadically introduced in South Africa and naturalised locally in temperate North America.
Preliminary conservation status (IUCN 2016). Solanum nigrum is a widely distributed amphitropical species across temperate and subtropical areas in the Old World; it can be assigned a status of LC (Least Concern; Table 7).
Discussion. Solanum nigrum, the type species of the genus Solanum, is a widespread weed with much morphological variation recognised at various infraspecific levels by many different authors (e.g. Linnaeus 1753; Opiz 1843). There are almost 100 names associated with the taxon and the status of some of these remains uncertain due to difficulty in finding types but we include them here based on their descriptions (but see Doubtful species). Here, we adopt an inclusive and broad concept of the species and recognise all infraspecific taxa under a single, more widespread and morphologically variable species. Two of the most commonly recognised infraspecific units include S. nigrum subsp. schultesii (Opiz) Wessely (villous, with glandular hairs) and S. nigrum subsp. nigrum (eglandular). Previous studies have found no support for the recognition of these or any other infraspecific taxa within S. nigrum based on morphological (Henderson 1974), seed protein (Edmonds and Glidewell 1977) or molecular marker data (Dehmer 2001;Dehmer and Hammer 2004;Olet 2004;Manoko 2007).
We do not include material identified as S. nigrum in recent African regional floras (Edmonds 2006a(Edmonds , 2006b(Edmonds , 2012 in our circumscription of this species. We follow Olet (2004) and Olet et al. (2011) and consider this material to represent the wild form of S. scabrum. In Africa, we consider only material from northern Africa around the Mediterranean and a few specimens (probably introduced from Europe) from South Africa to be true S. nigrum. Both S. nigrum and S. scabrum are hexaploids and morphologically similar, but can be distinguished on the following suite of morphological characteristics; Solanum nigrum has leaves with rather indistinct petioles, inflorescences with the flowers spaced along the rhachis, acute calyx lobes that are more or less appressed to the berry in fruit, and berries that not markedly shiny and often have stone cells (particularly in Asia). Solanum scabrum has distinctly petiolate leaves, the flowers are usually tightly congested at the tips of inflorescences or inflorescence branches, the calyx lobes are rounded, irregular and strongly reflexed in fruit and the berries are shiny with thick pericarp and lack stone cells. In addition, the fruiting pedicels of S. nigrum are spreading to somewhat recurved, while those of S. scabrum are erect and strongly spreading.
Throughout its range in Europe and into Eurasia as far as western China, S. nigrum is sympatric with S. villosum. The simplest distinguishing character is mature berry colour; S. villosum has red, orange or yellow berries, while those of S. nigrum are black or green. Many old collections, however, do not state berry colour on the label, so identification can be difficult. Calyx lobes are useful for distinguishing these taxa; S. nigrum calyx lobes are usually deltate and acute, with sharp triangular sinuses, while those of S. villosum are longer, usually rounded at the tip and the sinuses are broad and quite transparent (see description of S. villosum), leaving a paler "window" just below the sinus in flower buds and early flowers. The shiny, translucent berries of S. villosum (mostly slightly ellipsoid) usually dry blackish-brown, but are distinct from the matte, more opaque berries of S. nigrum. Neither species has stone cells in Europe, but in Asia, S. nigrum usually has 2 (or occasionally more) stone cells in the berries. Both species retain pedicels after fruits drop, but S. nigrum is not as extreme in this regard and often plants are found with old inflorescences with no remaining pedicels.
Solanum nigrum has been considered native only to Europe, but our study of populations of this widespread weed across its range has shown that the largest morphological variation can be observed in Asia. Populations of S. nigrum from Asia have more stone cells in the fruit and the plants have a more delicate look overall with longer peduncles and often fewer flowers per inflorescence. Material from Asia has been described as different taxa (e.g. S. guanchounense, S. chenopodiifolium) but the variation is continuous across the range, with European populations being more invariant (except in leaf shape and indumentum). Populations in Europe represent a relatively monomorphic set of populations compared to material from China and eastern Asia. We therefore consider that the species is native to the entire Eurasian area, with limited introductions to North America. North American material we have seen appears most similar to European plants based on morphology, suggesting the introduction to North America came from European populations, but this has not been tested genetically.
Australian populations of S. nigrum could have originated either from Europe or from Asia. In general, S. nigrum in Australia does not seem to have stone cells in general and plants fall into two continuously variable groups: one is similar to classic European S. nigrum and the other is more similar to plants from eastern and south-eastern Asia.
Solanum nigrum is an autoalloploid species, now thought to have originated from a tetraploid S. villosum and a diploid S. americanum by spontaneous amphiploidy (Edmonds 1979a;Ganapathi andRao 1986b, 1986c;. Cytogenetic and crossing studies show high fertility and regular pairing of bivalents at meiosis in crosses of S. villosum, S. retroflexum and S. americanum with S. nigrum (Edmonds 1979a; Ganapathi and Rao 1986b, 1986c, 1986d. Of the two tetraploid species, S. villosum and S. nigrum are sympatric at least across parts of their native ranges which would make it more likely that S. nigrum is an autoalloploid derived from the autopolyploid S. villosum and the diploid S. americanum. Molecular analyses have now shown that the two hexaploids S. nigrum and S. scabrum share a parental species with the tetraploid S. villosum . Artificially produced hexaploids from tetraploid crosses of S. villosum and S. americanum have been shown to be fertile and represent the glandular variant of S. nigrum (sometimes recognised as subsp. schultesii (Opiz) Wessely; Edmonds 1979a). It is hence becoming more clear that the tetraploid parent of S. nigrum is S. villosum and not S. retroflexum. Artificial hexaploids have been produced using S. villosum and S. americanum by several authors and the artificial hexaploids resemble S. nigrum morphologically (Tandon and Rao 1964;Rao 1969, 1972;Soria and Heiser 1959;Edmonds 1979a). Reciprocal backcrossing of the artificial hexaploids with S. nigrum results in a high fruit set (Venkateswarlu and Rao 1969Rao , 1972Edmonds 1979a), supporting the hypothesis that S. villosum and S. americanum are the parent species of S. nigrum. The autoallopolyploid origin of S. nigrum has been suggested by previous authors (Magoon et al. 1962;Rao 1971). In the light of the current molecular evidence combined with the accumulating evidence from cytological and crossing studies, the alternative hypotheses on the origin of S. nigrum as an autohexaploid (Jørgensen 1928;Nakamura 1935Nakamura , 1937 and an allopolyploid derived from three distinct genomes (e.g. Tandon andRao 1964, 1966a;Henderson 1974;Edmonds 1979a) are becoming less likely.
In parts of eastern England, S. ×procurrens A.C.Leslie (Leslie 1978), a sterile tetraploid hybrid between S. nitidibaccatum and S. nigrum, is locally established where the two species grown together (Stace 2010: 531;Stace et al. 2015). The hybrid has also been recorded in New Zealand (Webb et al. 1988). These plants are intermediate between the two species, with glandular pubescence and black berries with somewhat accrescent calyx lobes. A good description and distribution map for this local hybrid can be found in Stace et al. (2015). We have not seen convincing material from elsewhere in Europe of this hybrid, but it potentially occurs wherever S. nitidibaccatum and S. nigrum co-occur. As it is sterile, however, it does not spread or persist.
Linnaeus (1753) recognised six varieties of his S. nigrum, of which four are now considered distinct species (var. patulum = S. americanum; var. villosum = S. villosum; var. guineense = S. scabrum; var. virginicum = S. emulans Raf.). Henderson (1974) lectotypified S. nigrum with the single sheet in the Linnean herbarium (LINN 248.28) corresponding to this species. In the protologue, Linnaeus (1753) cited several other elements and it is from these that we select the lectotype for var. vulgare while, for var. judiacum, he cites no elements. It is possible that a specimen from his herbarium was the basis for this infraspecific epithet and that the sheet in LINN is that referred to by this name.
In describing S. judaicum, von Besser (1809) did not specifically cite Linnaeus's varietal name, so we have assumed he was coining a new name, rather than making a combination.
The name S. cestrifolium has a complex history; we can find no place of publication for "Solanum cestrifolium Jacq." as cited by Sprengel (1825) and Weinmann (1824:100; in synonymy with his nomen nudum S. besserianum, see Doubtful names under S. besseri Weinm. ex Roem. & Schult.). The name S. cestrifolium has also been attributed to Willdenow by Gussone (1825, as a nomen nudum) and subsequently validated by Colla (1835); this epithet refers to plants now considered part of the species S. bahamense L. (Strickland-Constable et al. 2008). We have not lectotypified S. cestrifolium Jacq. ex Spreng. in the hope that material amongst the cultivated holdings at W will reveal potential original material.
Blume (1826) cited no specimens for any of the names in his Bijdragen tot de flora van Nederlandsch Indië nor do many of the descriptions have specific localities. We have found a specimen labelled S. rhinozerothis in Blume's hand in L (L.2883159) that we here select as the neotype for that species, but have not found any material directly attributable to Blume that we could associate with S. uliginosum (see under Doubtful names).
The varietal epithet "atriplicifolium" was used by many authors to refer to plants of S. nigrum with dentate leaf margins. It appears to have been used in reference to a specimen that was annotated "Solanum atriplicifolium" by Narcisse Desportes, probably seen in Paris or Geneva. Georg Meyer of Hannover (1818) was the first botanist to effectively and validly publish this epithet and did so at the varietal rank. Dunal (1852) cited the same material and said that the collector was "Prost", though the G herbarium catalogue states the collector as Desportes. We select this G-DC (G00144334) sheet as the lectotype for S. nigrum var. atriplicifolium because it appears to be original material by way of locality and annotation. The combinations made by Don (1837) and Dunal (1852) are isonyms and therefore have no standing, but we include them here because they have been widely used and cited and other combinations have been made based upon them.
The various names coined by the amateur Czech botanist Philipp Maximilian Opiz and here recognised as synonyms of S. nigrum were all included by him in the "superspecies" S. nigrum and, from descriptions and key, represent leaf shape, pubescence and inflorescence size variations of that species. Opiz's enormous herbarium is housed mostly in PR (Kirschner et al. 2007) with duplicates in PRC and other major European herbaria. We have been unable to visit Prague to examine the no doubt extensive gatherings of S. nigrum and have found few unambiguous duplicates of the collections cited in the protologues. We therefore leave the typification of these infraspecific names until further study of Opiz's herbarium can be undertaken. The same is true for the infraspecific names coined by Johann Döll (1843), whose protologues cited some presumed collections, but no herbaria. Searches at KR reveal no original material and the A. Braun collections cited were probably at B and were destroyed. Again, these infraspecies refer to the highly variable populations of S. nigrum in central Europe. Döll (1843) attributed the infraspecific epithets var. chlorocarpum and stenopetalum to Braun; he was thus coining a new name "chlorocarpum" and not citing Spenner's earlier use of this epithet.
Solanum chenopodium, S. exarmatum and S. bidentatum were all coined by Rafinesque (1840) for European plants. He cited "S. nigrum var. undatum", a name never published, in the protologue of S. chenopodium and suggested that S. bidentatum was the same as "S. patulum of India". We here place these three in the synonymy of S. nigrum based on their rather meagre descriptions; Rafinesque's herbarium was destroyed, but occasionally fragments he sent to European herbaria survive (e.g. material relating to S. emulans Raf.) Dunal (1852) described several varieties of his complex taxon S. pterocaulum (in 1852 written as pterocaulon); most of these correspond to S. scabrum. His var. deppei was described from living material "v.v. Hort. Monsp."; a sheet in MPU (MPU310704) labelled "Solanum deppei. In hortis bot. cultum" is here selected as neotype for this name.
A single collection of a plant from Nepal cultivated in Avignon was cited in the protologue of S. guineense var. nepalense (Dunal 1852), housed in "h. Requien". A sheet at AV clearly labelled as "S. guineense β nepalense Prodr." is most likely original material for the name and we designate this as the lectotype.
Solanum roxburghii was coined by Dunal (1852) as a replacement for "S. rubrum" as used by Roxburgh (1824) in his Flora Indica. Dunal cited the publications of Roxburgh (1824, but with the incorrect page number of 216 rather than 246) and Nees van Esenbeck (1837) and an illustration by Wight, but cited no herbarium material. We consider the illustration in Wight (1843) as the only unambiguous original material for this name and designate it as the lectotype for S. roxburghii. Both the citations of "Solanum rubrum" are based on the epithet of Miller and/or Linnaeus and are not at all clear. Differentiating S. nigrum from S. villosum (both which occur in India) can be difficult without ripe berries and, since berry colour in the original hand-coloured illustration at E is green, we are certain the Wight illustration depicts a plant of S. nigrum, with flowers spaced along the inflorescence and sepals that are not reflexed in fruit. We therefore designate an epitype from amongst the sheets collected by Wight (E00718973) to fix the application of this name. Early authors, such as Roxburgh and Nees van Esenbeck, included both red/orange and black-fruited plants in their circumscriptions of both S. nigrum and S. rubrum. The sheets in the East India Company herbarium at K (see de Candolle and Radcliffe-Smith 1981;Noltie 2005) are a complex and confusing mixture of S. americanum and S. villosum; none of these specimens matches the illustration as well as does the E sheet we select here as the epitype. This again illustrates the difficulty that early authors had with these very similar plants and the dangers of assuming that collections are duplicates.
Miquel (1857) recognised several forms of S. nigrum in his broad species circumscription. His forma judiacum was specifically coined to encompass S. judaicum Besser in the sense of Blume (1826), but excluding Besser's material. We therefore consider this the coining of a new name and not a new combination based on Besser's S. judaicum; the lectotype selected is a sheet in L (L2880952) with the locality "in uliginosis circa Buitenzorg" as cited by Blume and in Blume's hand.
The names coined by the Hungarian botanist Pál Kitaibel were published posthumously by Kanitz (1863) and are largely illegitimate (some were used in earlier publications by Schultes, see discussion under S. villosum). Solanum hirsutum and S. acutifolium were published as alternative names "Solanum hirsutum vel acutifolium" and therefore have the same type; we have selected the sheet in the Kitaibel herbarium at BP with the locality matching that in the protologue ("ex itinere Arvensi", BP [Herb. Kit. fasc. IX: 103]).
We have selected a specimen collected by Schur (LW00210121), but with a different date of collection and exact locality, as the neotype for S. nigrum var. macrocarpum; searches in the other relevant herbaria revealed no original material. Edmonds (2012) only lectotypified one of the varieties of S. nigrum from Lowe's Manual Flora of Madeira (1872). Lowe's var. hebecaulon cited a single locality and date "Levada de Sta. Luzia, above Funchal, Feb"; no specimens corresponding exactly to that are found in BM or at K.
Solanum probstianum was described from material cultivated in Hungary from seeds sent by Rudolf Probst to Sandor Polgár in 1932. Although no specific specimens were cited in Polgár's protologue (in Probst 1938), there are many specimens annotated "Solanum probstianum" in Polgar's hand at BP that are clearly cultivated and appear to be from this original seed collection. We have selected one of these with both flowers and fruits as the lectotype of S. probstianum [BP-272406], it bears a collecting number (4051) and was collected in July 1933. We do not consider the other sheets with this number as necessarily duplicates; the sheets do not have consistent collection numbers and may represent individual plants from the cultivated population collected on different dates in the same or different years.

Solanum nitidibaccatum
Distribution (Figure 27). Native to southern South America but sporadically to widely adventive in Europe, North America, Australia and New Zealand.
Ecology. Grows along roadsides, in disturbed and cultivated areas in the shade of trees and shrubs, in rocky and sandy areas; between sea level and 2,000 (-2,700) m elevation in its native range, between sea level and 2,400 m in the Old World primarily as a weed in cultivations.
Uses. None recorded; a weed of agriculture and actively controlled. Preliminary conservation status (IUCN 2016). Solanum nitidibaccatum is a relatively weedy species that is invasive where introduced; in its native range it is widespread and can be assigned a preliminary status of LC (Least Concern; Table 7). The EOO is relatively large even if considering only the native American range (1,591,444 km 2 ) and the assessment status does not change.
Discussion. Solanum nitidibaccatum is morphologically similar to S. sarrachoides and has been treated under that taxon in many previous treatments (e.g. Schilling 1981, Schilling and. Edmonds (1986) clarified the distinction between the two taxa, together with a discussion of the problems surrounding its correct identification and its complex synonymy and lectotypification. Solanum nitidibaccatum was treated as a subspecies of S. physalifolium (Edmonds 1986). Solanum physalifolium is not known from the Old World and is endemic to South-Central Andes of Argentina, Bolivia and Peru to elevations between 2,000 and 2,900 m; distinguishing features of that species can be found in the key in Barboza et al. (2013). Solanum nitidibaccatum is a diploid species native to the south-eastern parts of South America and within the Old World is morphologically most similar to S. sarrachoides, with which it has been confused. The two species are best distinguished by the complete inclusion of buds in calyx before anthesis, the larger stone cells in berries and the more erect habit of S. sarrachoides (see key in Barboza et al. 2013). Solanum nitidibaccatum has shorter and more ovoid anthers compared to S. sarrachoides, where anthers are more elongate-ellipsoid and the fruiting calyx of S. nitidibaccatum does not cover the berry as much as does that of S. sarrachoides.
Solanum nitidibaccatum has been introduced extensively to other parts of the world where it has become a prolific and successful weed of disturbed sites usually associated with agriculture of the wool trade. Trade with South America -particularly the importation of grain, seeds and the spreading of wool 'shoddy' -has been largely responsible for its introduction into Europe, with one of its common European names being the Argentinian nightshade. The taxon is now a widespread adventive in Europe where it is rapidly becoming naturalised and often forms extensive populations. It has been introduced into Australia on a number of occasions, where it persists as a weed of cultivation and is sparingly established in all States (Henderson 1974;Symon 1981). The species is locally abundant throughout North America  where it is particularly widespread in the Pacific States and the West (Bohs in press). It was introduced into the South Island of New Zealand around 1968 where it rapidly became established and is now also found in northern parts of North Island (Healy 1974). It also has been sparingly introduced into equatorial regions of Africa (see Appendix 2).
In parts of eastern England, S. ×procurrens A.C.Leslie (Leslie 1978), a sterile tetraploid hybrid between S. nitidibaccatum and S. nigrum, is locally established where the two species grow together (Stace 2010: 531;Stace et al. 2015). The hybrid has also been recorded in New Zealand (Webb et al. 1988). These plants are intermediate between the two species, with glandular pubescence and black berries with somewhat accrescent calyx lobes. A good description and distribution map for this local hybrid can be found in Stace et al. (2015). We have not seen convincing material from elsewhere in Europe of this hybrid, but it potentially occurs wherever S. nitidibaccatum and S. nigrum co-occur. As it is sterile, however, it does not spread or persist.
The amateur Swedish botanist Carl Blom rarely cited herbaria for his names; we have selected the sheet in GB, where he worked, as the lectotype of his var. integrifolium.  Description. Annual or short-lived sprawling to erect perennial herbs to 1 m tall, subwoody and branching at base. Stems spreading to decumbent, terete or sometimes slightly ridged, green to yellow-green, older stems greenish-grey, not or occasionally somewhat hollow; new growth densely to sparsely pubescent with simple, antrorse, uniseriate, translucent, eglandular or sometimes glandular trichomes, these 4-6-celled, 0.5-1 mm long; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, 1.5-8.0(-17) cm long, 1-4 -(9) cm wide, elliptic to slightly ovate, very variable in size, membranous, green, concolorous, without smell; adaxial surface glabrous or sparsely and evenly pubescent with simple uniseriate ca. 4-celled trichomes to 0.5 mm long; abaxial surfaces glabrous or sparsely pubescent with simple uniseriate trichomes along the veins; major veins 3-8 pairs, not prominent; base cuneate, decurrent on the petiole; margins entire or shallowly toothed, if present the teeth acute; apex acute to acuminate; petioles 0.5-3 cm long, sparsely pubescent with antrorse simple uniseriate trichomes like those of the stems. Inflorescences 1-2 cm long, internodal, unbranched but very rarely furcate, umbelliform to sub-umbelliform, with 3-7 flowers clustered near the tip of the rhachis, sparsely pubescent with antrorse simple uniseriate 3-4-celled trichomes like those of the stems; peduncle 1-3 cm long, straight and stout; pedicels 0.4-0.8 cm long, < 0.3 mm in diameter at the base, ca. 0.3 mm in diameter at the apex, filiform, nodding, pubescent like the peduncle, articulated at the base; pedicel scars clustered near the tip of the rhachis, often the lowest flower ca. 0.5 mm spaced from the rest. Buds ellipsoid, the corolla strongly exserted from the calyx tube long before anthesis. Flowers 5-merous, all perfect. Calyx tube 1-2 mm long, conical, the lobes often unequal, the lateral two largest 1-1.2 mm long, 0.5-0.6 mm wide, the top and lowermost 0.4-1.0 mm long, 0.3-0.5 mm wide, long triangular often with a rounded tip, glabrous or sparsely pubescent with antrorse simple uniseriate trichomes ca. 0.5 mm long. Corolla 6-10 mm in diameter, white or white with a purplish tinge, stellate, lobed ca. 1/2 way to the base, the lobes 3.0-4.2 mm long, 1.0-1.2 mm wide, spreading to reflexed, densely papillate on tips and margins. Stamens equal; filament tube < 0.1 mm long; free portion of the filaments 0.5-1.0 (-1.5) mm long, glabrous or adaxially pubescent with tangled simple uniseriate trichomes; anthers 1.2-1.6 mm long, 0.7-1.0 mm wide, ellipsoid, yellow, somewhat sagittate at the base, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary rounded, glabrous; style 3-4 mm long, strongly curved in the distal 1/4, densely pubescent with simple uniseriate trichomes 0.2-0.5 mm long, these tangled in the basal 1/2 to 2/3 of the length, not exserted beyond anthers and only the stigma visible outside the anther cone; stigma capitate, the surfaces minutely papillate. Fruit a globose berry, 4-10 mm in diameter, green or bluish-black at maturity, the pericarp thin, matte; fruiting pedicels 0.7-1.5 cm long, ca. 0.5 mm in diameter at the base and the apex, erect or spreading, becoming yellow, falling with the mature fruits, not persistent; fruiting ca-lyx lobes not accrescent, the tube less than 1 mm long, the lobes 1.2-1.7 mm long, appressed to the basal quarter of the berry, occasionally somewhat spreading, never strongly reflexed. Seeds 50-100 per berry, 1.2-2.2 mm long, 0.7-1.8 mm wide, flattened reniform, pale yellowish-tan, the surfaces minutely pitted, thin and the embryo clearly visible, the testal cells rectangular to pentagonal in outline. Stone cells (0-)2(-4) per berry, >0.5 mm in diameter, brown. Chromosome number: 2n=6x=72 (Henderson 1974;Symon 1985).
Distribution (Figure 30). Native in the Pacific islands, from Australia, Papua New Guinea and New Zealand, to Taiwan and Hawaii, west to the Pitcairn Islands and Rapa Nui (Easter Island).
Ecology. Grows in disturbed areas, along roadsides and field edges; between sea level and 2,600 m elevation in a wide variety of habitats.
Uses. Leaves eaten as greens throughout the species range. Preliminary conservation status (IUCN 2016). Solanum opacum is a relatively widespread species across the Pacific; it can be assigned a preliminary status of LC (Least Concern; Table 7) on a global scale, but local country assessments may differ. The species has a very scattered distribution in the Pacific and, although its overall range is very large, the land area it occupies is small.
Discussion. Solanum opacum is extremely similar to S. americanum; both species have minute flowers with anthers usually less than 1.5 mm long. They co-occur across the Pacific, but can be distinguished easily, particularly in fruit. Solanum opacum has matte berries that are green or greyish-purple at maturity, with appressed or slightly spreading calyx lobes, while S. americanum has very shiny berries that are black or dark purple at maturity and calyx lobes that are very strongly reflexed. The pedicels of S. americanum remain on the plant as fruits fall, while those of S. opacum drop with the mature berries. In flower, the relative length of filament to anther is a useful distinguishing character; S. opacum has filaments that are as long as or slightly longer than the anthers, while the filaments of S. americanum are always shorter than the anthers.
Our circumscription of S. opacum encompasses a much wider distribution than that of Henderson (1974), who treated only the Australian populations. The treatments of "Solanum nigrum" or "Solanum americanum" in the Pacific could apply to either S. opacum or S. americanum. Degener (1945) records the use of morelloid species in Hawaii for both food and medicine; both species occur there.
Solanum opacum is hexaploid and, based on network analysis of arbitrary amplified DNA markers,  suggested that Australian populations of S. retroflexum were a possible tetraploid parent of S. opacum. The putative diploid parent is S. chenopodioides, S. nitidibaccatum or some other closely related species . Morphologically, S. retroflexum somewhat resembles S. opacum, but the shared molecular markers could also come from a common progenitor of the two polyploid species. Henderson (1974) Henderson 1974, pg. 39: NSW [NSW125341]; isoneotypes: BM [BM000900380], K, MEL)) because he could find no original material corresponding to the collector or locality cited in the protologue ("E Nova Hollandia. Semina communicavit Listemann") and presumed it to have been in Berlin and subsequently destroyed. However, recent digitisation of historical material in European herbaria has uncovered original material not seen by Henderson (http://plants.jstor.org/stable/viewer/10.5555/al.ap.specimen.hbg511471) that was annotated as "lectotype" in 1974 by J.M. Edmonds, but never published as such. The fact that original material has been found means that Henderson's (1974) neotypification must be set aside (McNeill et al. 2012, Art. 9.19) and we designate the sheet in HBG (HBG511471) as the lectotype of S. opacum. It matches the wild-collected plants selected by Henderson exactly.
Solanum forsteri was named in honour of the Forster's (father Johann and son Georg, who accompanied Captain Cook on the HMS Resolution from 1772 to 1775) and we have selected the sheet collected by them on Easter Island (BM000900372) as the lectotype. This specimen is mounted together with a collection of S. americanum that is on different paper (white rather than the blue associated with Forster's material), showing the difficulty that early botanists (and this holds true still today) had in distinguishing these two species with minute anthers that co-occur across the Pacific.  Description. Annual, decumbent or prostrate herbs, the young plants sometimes erect, up to 15 cm tall often rooting at the lower nodes, forming dense patches, the branches to ca. 1 m long. Stems decumbent or ascending, terete or somewhat angled with ridges, green, older stems yellowish-brown, not markedly hollow; new growth pubescent with simple, spreading, uniseriate, translucent, eglandular trichomes, these 0.5-1 mm long, to or nearly glabrous; older stems glabrous. Sympodial units difoliate, the leaves not geminate. Leaves simple, 2.5-9 cm long, 2.5-7.5 cm wide, broadly ovate, thinly membranous, green, concolorous, without smell; adaxial surfaces glabrous to sparsely pubescent with simple hairs to 0.5 mm on the major veins; abaxial surfaces glabrous; major veins 3-4 pairs; base long attenuate, decurrent on the petiole; margins 3-lobed nearly to the midrib, rarely the lateral lobes themselves lobed, the terminal lobe ovate, the lateral lobes asymmetrically ovate or lanceolate-ovate, acute at the tips, the sinuses sometimes sparsely ciliate; apex acute; petioles 0.5-2 cm, winged to the base, glabrous or sometimes sparsely ciliate near the base. Inflorescences 1.2-2.5 cm, internodal or often just below a node, unbranched or rarely with a few branches, the flowers spaced along the rhachis, with 4-9 flowers, glabrous to sparsely pubescent; peduncle 0.7-1.4 cm long, delicate; pedicels 3-5 mm long, 0.2-0.3 mm in diameter at the base and at the apex, filiform, spreading, articulated at the base; pedicel scars spaced 1-5 mm apart. Buds ellipsoid, the corolla completely covered by the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.5-2 mm long, cup-shaped, the lobes ca. 0.75-1.5 mm long, less than 1 mm wide, lanceolate-oblong, the tips acute, glabrous. Corolla ca. 7 mm in diameter, white or rarely light violet, rotate-stellate, lobed ca. 1/2 way to the base, the lobes 1.5-2.5 mm long, 1-2 mm wide at the base, reflexed or spreading at anthesis, abaxially minutely white-puberulent on the tips of the lobes, glabrous adaxially. Stamens equal; filament tube minute; free portion of the filaments 0.5-1 mm long, adaxially pubescent with tangled uniseriate trichomes; anthers 1.6-2 mm long, 0.7-0.8 mm wide, oblong or ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary glabrous; style 2.3-3.3 mm long, glabrous or sparsely pubescent in the lower part where included in the anther cone, exserted 0.5-0.8 mm beyond anthers; stigma capitate, the surface minutely papillate, green in live plants. Fruit a depressed-globose and bilobed (especially when young) berry, 6-8 mm in diameter, pale yellow, the pericarp thin and somewhat shiny; fruiting pedicels 4-7 mm long, 0.5-0.7 mm in diameter at the base and at the apex, spreading, recurved at the base to hold the fruit downwards, nearly in contact with the soil, dropping with the mature fruit, not persistent; fruiting calyx not markedly accrescent but the lobes somewhat elongating in fruit, the tube 2-3 mm long, the lobes 2-3(-4) mm long, covering the basal 1/3 of the berry, the tips somewhat recurved. Seeds 20-30 per berry, 1.5-1.6 mm long, 1.2-1.6 mm wide, flattened reniform, light yellow, the surfaces pitted, the testal cells sinuate in outline. Stone cells 2(4) per berry, 2 larger and apical (1-1.5 mm in diameter), the other 2 equatorial, smaller, 0.5-0.6 mm in diameter. Chromosome number: 2n=2x=24 (Moscone 1992;Moyetta et al. 2013).
Distribution (Figure 33). Native to north-western and central Argentina, northern Chile and Bolivia and apparently very locally naturalised in New South Wales (Australia).
Ecology. Grows in disturbed sites, along roadsides and field margins, on rocky, sandy or clay soils; between (50-) 1,400 and 3,000 (-3,700) m in its native range, near sea level in Australia.
Common names. None recorded for the Old World.
Uses. None recorded for the Old World. Preliminary conservation status (IUCN 2016). Solanum palitans is a widespread species in its native range, has a relatively large EOO across its entire distribution and can hence be assigned a preliminary status of LC (Least Concern; Table 7). It is only locally established in coastal New South Wales. The preliminary assessment based on South American distribution is still LC based on EOO (898,907 km 2 ).
Discussion. Solanum palitans is distinct amongst the species of morelloids occurring in the Old World in its combination of uniformly 3-lobed, thin membranous leaves and pale yellow mature fruits. The species has a creeping habit, with stems growing close to the ground extending up to 3 m and often rooting at nodes. Outside of its native range in South America, it is only found in Australia, but may appear in other areas of suitable habitat given time. Details of its variability and habitats in Argentina can be found in Morton (1976) and Barboza et al. (2013).
Like other adventive members of this group, it is likely to have been introduced to Australia with wool waste from Argentina. The first collection cited in Symon (1981) is from 1911 and the most recent we have seen is from 2013. It appears not to be spreading from New South Wales, but could also occur in New Zealand due to habitat similarities, although we have seen no specimens of S. palitans from there. Symon (1981) records that it is not eaten by stock, perhaps accounting for its limited distribution.  Description. Annual or short-lived prostrate or sprawling perennial herbs to 0.5-1.5 m tall, subwoody and branching at base. Stems spreading, usually strongly ridged  with pseudospinose dentate processes, green, older stems brown or grey, usually hollow; new growth densely pubescent with simple, spreading, uniseriate, translucent, mixed glandular and eglandular trichomes, these 7-10-celled, 1.0-1.5 mm long; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, 2.5-7 cm long, 1.3-4 cm wide, smaller at distal ends of branches, ovate, widest in the lower third, membranous, green, concolorous, smell not known; both surfaces evenly pubescent with simple uniseriate mostly eglandular trichomes like those on stem; major veins 4-5 pairs; base cuneate; margins entire or shallowly toothed in the basal half; apex acute to acuminate; petioles 0.5-2 cm long, pubescent with trichomes like the leaves. Inflorescences 1-2.5 cm long, opposite the leaves, unbranched, subumbelliform to racemose, with 2-5(-6) flowers clustered at the tip, pubescent with uniseriate trichomes like those of the stems; peduncle 0.3-1.5 cm long, straight; pedicels 0.7-0.8(-1) cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, slender, spreading, pubescent with simple uniseriate trichomes like the rest of the inflorescence, articulated at the base; pedicel scars clustered in the apical portion of the inflorescence rhachis, lowermost scars ca. 2 mm apart, the rest overlapping at the distal end. Buds ellipsoid, densely pubescent, the corolla at least 1/2 way exserted from the calyx tube until just before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.5-2 mm long, conical, the lobes 1-1.5 mm long, 0.9-1.4 mm wide, elongate-deltate, rounded at the tips, densely pubescent with simple uniseriate trichomes like the rest of the inflorescence. Corolla 8-14 mm in diameter, white to pale violet ("blue") or white with purple venation, stellate, lobed nearly to the base, the lobes 4-6 mm long, 2-2.5 mm wide, spreading at anthesis, abaxially moderately pubescent with simple uniseriate 2-3-celled trichomes, these denser near the tips and margins, also papillate along the margins and tips, adaxially glabrous. Stamens equal; filament tube minute; free portion of the filaments 0.5-1 mm long, densely pubescent adaxially with tangled simple trichomes; anthers 2-2.5 mm long, ca. 1 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary conical, glabrous; style 3-5 mm long, densely pubescent with tangled simple trichomes in the basal portion inside the anther tube, exserted ca. 2 mm beyond the anther cone, often elongating early and protruding from unopened buds; stigma capitate, the surfaces minutely papillose, colour in live plants not known. Fruit a globose berry, 4-6 mm in diameter, purple or black at maturity, the pericarp thin and matte; fruiting pedicels 0.9-1.2 cm long, ca. 0.75 mm in diameter at the base and at the apex, spreading, not falling with the fruit, remaining on the plant and persistent on older inflorescences; fruiting calyx not accrescent, the tube ca. 1 mm long, the lobes 1.5-2.5 mm long, appressed to the berry, spreading and hyaline, the tips slightly reflexed. Seeds ca. 20 per berry, ca. 1.5 mm long, ca. 1 mm wide, not markedly flattened, tear-drop shaped with a subapical hilum, pale beige, the surface minutely pitted and the lateral testal cell walls elongate and the seed appearing hairy, the testal cells pentagonal in outline. Stone cells 4-6(-10), often found near the pedicel junction at the base of the berry. Chromosome number: 2n=4x=48 (Morton 1993).

Solanum pseudospinosum
Distribution (Figure 36). Endemic to the escarpment running from the island of Bioko (Fernando Po) in Equatorial Guinea to Lake Oku in Cameroon; most collections we have seen are from the slopes of Mount Cameroon.
Ecology. Grows at forest margins, in clearings and along roadsides; between 2,100 and 4,000 m elevation.
Common names. Cameroon: afom. Uses. None recorded. Preliminary conservation status (IUCN 2016). Solanum pseudospinosum is a relatively narrow endemic with a relatively small AOO (48 km 2 , EN) and EOO (4,009 km 2 , EN; Table 7). Based on this narrow distribution and the fragmented high elevation habitat, it is given a preliminary conservation status of EN (Endangered). Most collections are from the protected area of Mount Cameroon and populations outside this national park will be vulnerable.
Discussion. Solanum pseudospinosum is a high elevation species that, in our circumscription, only occurs along the so-called Cameroon line that is along the junction of the Congo and West African cratons (Fitton 1987). We recognise the East African plants identified as S. pseudospinosum by Edmonds (2012) as high elevation, particularly pubescent populations of the more widespread S. tarderemotum. The key characters distinguishing the two species are the pedicel that remains on the plant after fruit drop in S. pseudospinosum, while those of S. tarderemotum drop with the berries Figure 36. Distribution of Solanum pseudospinosum. and the prominent articulations at the bases of the pedicels in S. tarderemotum. Other differences of S. pseudospinosum, but less easy to see, are the elongate, spathulate calyx lobes in fruit (those of S. tarderemotum are less hyaline and usually pointed) and the few-flowered congested inflorescences (as opposed to elongate, rather evenly spaced flowers along the rhachis in S. tarderemotum). Solanum pseudospinosum is also sympatric with wild populations of S. scabrum from which it can be distinguished by the dense spreading pubescence, the presence of stone cells in the fruit and the somewhat accrescent calyx lobes appressed to the berry.
The Cameroon line along which Solanum pseudospinosum occurs runs from the island of Bioko to the Tchabal Mbabo plateau and is of volcanic origin with activity beginning the Cretaceous period, but peaking in the Pliocene and continuing to the present (Wright et al. 1985). The island of Bioko is Pliocene in age (Wright et al. 1985) and has been connected and separated from the mainland several times throughout the Pleistocene. Smith et al. (2000) found only weak relationships between populations of two bird species along the Cameroon line, suggesting they evolved by allopatry.
Plant diversity in this area is amongst the highest in tropical Africa (Sosef et al. 2017), but despite having within it some well-sampled units (e.g. Mount Cameroon), the northern extent of the escarpment is very poorly sampled (Sosef et al. 2017: 12, fig.  7). Better field knowledge of the distribution of S. pseudospinosum, coupled with better knowledge of its habitat preferences and genetic structure, will help unravel the evolutionary history of this narrowly endemic species.
Solanum pseudospinosum is a tetraploid species with unknown parentage (Olet et al. 2015). The species has not been included in any previous crossing and molecular studies that have focused on understanding the parental origin of the hexaploid species S. nigrum and S. scabrum (e.g. Edmonds 1977Edmonds , 1979aGanapathi and Rao 1985, 1986b, 1986c, 1987a, 1987bJacoby et al. 2003;Jacoby and Labuschagne 2006;van der Walt et al. 2008;. It could represent one of the tetraploid parents of the hexaploids and should be included in further studies focused on understanding the origin of the polyploids. All of the species described by Bitter (1912a) and here recognised as synonyms of S. pseudospinosum were described from collections housed at B that were destroyed in World War II (Vorontsova and Knapp 2010) and we have placed these in synonymy based on their very detailed descriptions. It is to be hoped that duplicates of these collections will eventually be found in herbaria not yet investigated or digitised. The differences between this species and that of C.H. Wright were very small, based on leaf size and on numbers of stone cells; we consider these minor differences insignificant.  Description. Perennial small upright herbs up to 30 cm tall, subwoody at base, perennating via underground rhizomes. Stems decumbent or ascending, delicate, terete or somewhat angled with ridges, not markedly hollow; new growth pubescent with simple, appressed, uniseriate, translucent, eglandular trichomes, these 1-6-celled, 0.2-0.5 mm long or nearly glabrous; older stems glabrous or glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, 1.0-5.0 cm long, 0.5-3 cm wide, ovate to narrowly elliptic, pale green, concolorous, without smell; adaxial surface glabrous or sparsely pubescent along leaf lamina and margins with simple, uniseriate trichomes like  those on stem; abaxial surface sparsely pubescent with similar trichomes but the pubescence denser along the midrib; major veins 3-4 pairs; base attenuate, decurrent on the petiole; margins sinuate to entire; apex acute to obtuse; petioles 0.5-1.7 cm long, with scattered simple, appressed, uniseriate eglandular trichomes like those on stem. Inflorescences 1-3 cm long, generally internodal, simple or rarely furcate, umbelliform to sub-umbelliform, with (2-)4-6 flowers clustered at the tip, glabrous or with scattered simple, appressed, uniseriate eglandular trichomes like those on stem; peduncle (1.3-)1.5-2.6 cm long, delicate; pedicels 6-13 mm long, 0.5-1 mm in diameter at the base, ca. 1 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 0-2.5 mm apart. Buds globose to broadly ovoid, the corolla strongly exserted from the calyx tube but only halfway exserted beyond the elongate and reflexed calyx lobes before anthesis. Flowers 5-merous, all perfect. Calyx tube (0.5-)1.7-2.0(-2.2) mm long, conical, the lobes 1.5-1.8 mm long, 0.7-0.9 mm wide, narrowly elliptic with long-acuminate to acute apices, glabrous to sparsely pubescent with simple uniseriate eglandular trichomes like those on stem. Corolla 9-16 mm in diameter, white to pale lilac with a yellow-green central portion near the base, stellate, lobed 1/2 way to the base, the lobes 5.0-6.7 mm long, ca. 3.0-3.5 mm wide, strongly reflexed at anthesis, later spreading, glabrous to sparsely pubescent abaxially with simple uniseriate trichomes like those of the stem but shorter. Stamens equal; filament tube minute; free portion of the filaments 1.0-1.2 mm long, adaxially pubescent with tangled uniseri-ate 4-9-celled eglandular trichomes to 0.5 mm long; anthers (3.0-)3.5-3.8 mm long, 0.7-1.0 mm wide, oblong-ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style ca. 6.3 mm long, densely pubescent with (1-)2-3-celled simple uniseriate trichomes in the lower 4/5, exserted 1-2 mm beyond the anther cone; stigma capitate to clavate, bilobed, minutely papillate, green in live plants. Fruit a subglobose berry, 8-10 mm in diameter, greyish-green at maturity, the pericarp opaque and glaucous; fruiting pedicels 12-15 mm long, ca. 1 mm in diameter at the base and at the apex, deflexed and often somewhat curved, dropping with mature fruits, not persistent; fruiting calyx not accrescent, the tube ca. 1 mm long, the lobes 1.5-2 mm long, appressed against the berry. Seeds >50 per berry, 1.8-2.0 mm long, 1.2-1.4 mm wide, flattened and tear-drop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells irregularly quadrate in outline. Stone cells 6-8, the 2 apical ones 1.5-2 mm in diameter, usually very closely paired, the rest equatorial and 1-1.2 mm in diameter, pale whitish-brown. Chromosome number: 2n=2x=24 (one individual with n=18 and chromosomal anomalies with supernumerary bivalents or univalents not segregating; Moscone 1992).

Solanum pygmaeum
Distribution (Figure 39). Native to central and coastal Argentina; a few specimens known from Europe arriving as seeds through wool shipments but these are not usually established as permanent populations.
Ecology. Grows in sandy and clay soils, along rail road tracks and road sides; between 100 and 1,000 m elevation in its native range, but brought only sporadically to Europe and North America via wool shipments and trade to ports at sea level and has not naturalised widely.
Common names. None recorded in Old World. Uses. None recorded. Preliminary conservation status (IUCN 2016). Solanum pygmaeum is widespread in its native range and can be assigned a preliminary status of LC (Least Concern; Table 7). Populations from the Old World are relatively ephemeral. Within the native range in South America, S. pygmaeum still has a relatively large EOO of 700,962 km 2 .
Discussion. Solanum pygmaeum is only occasionally collected in Europe, usually associated with wool waste. It is a plant that spreads by underground stems, so it is surprising that it has not become established; we include the species here so that old herbarium specimens can be identified and so that the species can be spotted if it does become established as climate changes.
The species is easy to distinguish from all other morelloids occurring in Europe by its large flowers (anthers > 3mm long), narrowly elliptic calyx lobes (1.5-1.8 mm long) and rhizomatous habit. Leaves are quite variable in size, but are usually narrowly elliptic, less often wider in the lower half.
We have selected the P duplicates that were part of the "Société cénomane d'exsicccata" as the lectotypes of var. integrifolium and var. sinuatodentatum because they are well-preserved and have both flowers and young fruits. The lectotype we have selected for var. hastatum is in an Argentinian herbarium (see best practice as outlined in Smith and Figueiredo 2011) and we have been unable as yet to trace original material of var. latifolium.  Description. Annual to perennial prostrate to erect herbs to 0.6 m tall, subwoody and branching at base. Stems sprawling, terete or ridged, 0.3-0.6 cm in diameter, if stems ridged the ridges sometimes spinescent, green to yellowish-brown, older stems straw coloured, not markedly hollow; new growth sparsely to densely pubescent with simple, spreading, uniseriate, translucent, glandular and/or eglandular trichomes, these 1-5(-8)-celled, 0.1-0.8 mm long; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, (0.5-) 1.5-7.5 cm long, 1.5-5.5 cm wide, rhomboidal to lanceolate, membranous, green, slightly discolorous, without smell; adaxial surface green, sparsely to densely pubescent with simple uniseriate trichomes like those on stem evenly spread along lamina and veins; abaxial surface slightly paler, more densely pubescent along veins and lamina; major veins 3-7 pairs; base truncate then abruptly attenuate along the petiole; margins shallowly toothed, the teeth rounded; apex acute, the tip sometimes rounded; petioles (0.5-) 1.5-3.5 cm long, sparsely to densely pubescent with simple uniseriate trichomes like those of the stems. Inflorescences 1.8-3.0 cm long, internodal, simple, sub-umbelliform, with 3-7 flowers clustered towards the tip of the rhachis, sparsely to densely pubescent with glandular and/or eglandular simple uniseriate trichomes like those on stems; peduncle 1.5-3.5 cm long, erect; pedicels 1.0-1.5 cm long, 0.3-0.6 mm in diameter at the base, 0.4-0.6 mm in diameter at the apex, recurving but not fully reflexed, pubescent like the peduncle, becoming woody, green or yellow-brown, articulated at the base; pedicel scars spaced 0-0.5 mm apart. Buds globose, the corolla 1/3 exserted from the calyx before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.0-1.7 mm long, campanulate, the lobes equal, 1.0-1.5 mm long, less than 1 mm wide, oblong with rounded tips, green, sparsely pubescent with simple uniseriate trichomes like of the inflorescence. Corolla 11-16 mm in diameter, white, with a yellow basal star, stellate, lobed to 1/2-2/3 towards the base, the lobes 5.0-6.0 mm long, 2.5-2.7 mm wide, spreading to reflexed, densely papillate-pubescent abaxially with simple uniseriate trichomes, these denser on tips and margins. Stamens equal; filament tube minute; free portion of the filaments 1.2-1.5 mm long, glabrous or adaxially pubescent with tangled 6-8-celled simple uniseriate trichomes; anthers 1.3-1.8(-2.0) mm long, 1.0-1.5 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying, the connective becoming brownish in dry material. Ovary rounded, glabrous; style 1.9-2.2 mm long, slightly curved, pubescent with simple uniseriate trichomes 0.2-0.5 mm long in the basal 1/3 where included in the anther cone, exserted 0.5-1.5 mm beyond anther cone; stigma capitate, the surface minutely papillate. Fruit a globose berry, 6-10 mm in diameter, purple-black at maturity, the pericarp thin, matte with a glaucous cast; fruiting pedicels 1.0-1.5 cm long, 0.4-0.6 mm in diameter at the base, 1.0-1.2 mm at apex, becoming woody, recurving to deflexed, pale green to yellow-brown, spaced 0-0.5 mm apart, not falling with the fruit, remaining on the plant and persistent on older inflorescences; fruiting calyx not accrescent, the tube 1.0-1.5 mm long, the lobes 1.5-2.0 mm long, strongly reflexed. Seeds (5-)12-35 per berry, 1.6-1.8 mm long, 1.3-1.5 mm wide, flattened and tear-drop shaped with a subapical hilum, yellow to brown, the surfaces minutely pitted, the testal cells rectangular to pentagonal in outline. Stone cells absent. Chromosome number: 2n=4x=48 (Henderson 1974;Randell and Symon 1976;Edmonds 1977Edmonds , 1983Symon 1981;Jacoby and Labuschagne 2006). Distribution (Figure 42). Endemic to southern Africa but has been introduced to Australia and was introduced as a garden plant to North America in the early 20 th century and now globally available through commercial seeds from online sources under the name "Garden Huckleberry".

Solanum retroflexum
Ecology. Grows in disturbed soil at watering holes, along dry watercourses, in shady places, in long grass, in Euphorbia candelabrum-Buxus zone, in dry hillsides and in disturbed areas along roads; between sea level and 1,800 (-2,300) m elevation.
Uses. Berries used raw and for jam (Viljoen 2011); leaves eaten as a pot-herb vegetable. Preliminary conservation status (IUCN 2016). Solanum retroflexum is widespread and can be assigned a preliminary status of LC (Least Concern; Table 7). Taking into account only collections from within the native range in Africa, the EOO is still very large (2,929,097 km 2 ) and the assessment does not change.
Discussion. Solanum retroflexum is a species that shows great variation in its indumentum, varying from nearly glabrous to densely pubescent with either eglandular or glandular trichomes. AFLP studies have shown that specimens of S. retroflexum with different indumentum types are genetically highly similar (Manoko 2007, as S. hirsutum (Vahl) Dunal, here recognised as a synonym of S. memphiticum). Developmental studies have shown that papillate glandular hairs are present on all young parts of Solanum plants (Seithe 1962(Seithe , 1979; see Morphology above), suggesting that, in the absence of other distinguishing features, glandular pubescence might not be taxonomically significant. We circumscribe S. retroflexum here to include both eglandular and glandular populations; this character is polymorphic in most species of morelloids in the Old World, perhaps due to genetic lability due to polyploidy.
The species can be distinguished from other Old World morelloids based on the combination of characters of few-flowered inflorescences with 3-7 flowers, relatively long filaments (1.2-1.5 mm long) compared to anther length (1.3-1.8(-2.0) mm), strongly reflexed calyx lobes in fruit and matte purple-black berries that lack stone cells and drop without the pedicels. Leaf shape is generally rhomboidal, which is characteristic of the species and helpful in distinguishing it from closely related S. nigrum and S. villosum. Calyx lobes are generally longer than in S. villosum, S. scabrum or S. nigrum. It can be distinguished from the morphologically similar S. villosum based on its opaque purple-black fruit, its pedicels that remain behind after fruits drop, deeply stellate corolla with long corolla lobes and the long filaments as compared to anther length.
Solanum retroflexum is cultivated commercially in South Africa in KwaZulu-Natal and Free State for jam production (Viljoen 2011) and farmers select individual plants with large berries to propagate for the next season. In one farm in KwaZulu-Natal, 10 tonnes of berries harvested were used to make 20,000 jars of "Umsobo" jam, most marketed in the Gauteng area. On other farms, S. retroflexum is cultivated along with S. chenopodioides and S. americanum and putative hybrid plants were found (Viljoen 2011). Leaves of S. retroflexum are also produced under irrigation in Limpopo province, for the commercial market in the local area (van Averbeke et al. 2007). The markets for both leaves and fruits are controlled by small scale rural traders in South Africa. Solanum retroflexum is a tetraploid species with unclear parentage. Previous studies have suggested that one of the contributing parents of the tetraploid S. retroflexum is the diploid S. americanum (Edmonds 1977), supported by crossing studies showing vigorous hybrids between the autotetraploid S. villosum derived from S. americanum and S. retroflexum (Ganapathi 1987). Jacoby and Labuschagne (2006), however, reported that crosses of S. chenopodioides and S. retroflexum are much more successful than crosses between S. retroflexum and S. americanum. Ganapathi & Rao (1980) also reported weak chromosome pairing at low frequency in hybrids between S. retroflexum and S. americanum. Molecular studies suggest that either S. chenopodioides or S. nitidibaccatum are the likely parental species of S. retroflexum (Jacoby et al. 2003;van der Walt et al. 2008;. Further molecular studies are needed to fully establish the parental species of S. retroflexum, but the current data from molecular and crossing studies suggests that S. chenopodioides or S. nitidibaccatum are the likely best candidates.
Solanum retroflexum or one of its close relatives has been suggested to have contributed to the origin of the hexaploid S. nigrum (Ganapathi and Rao 1986c). Most current evidence suggests, however, that S. villosum and S. americanum were the parents of S. nigrum (Edmonds 1979a;Ganapathi and Rao 1986b;. In describing S. retroflexum, Dunal (1852) cited two elements; one from Saudi Arabia ("in Arabia circa Taifa") and the other from South Africa ("caput Bona Spei, Drege"). He then used two different collections held at G-DC to describe the varieties. The speci-men from Saudi Arabia corresponds to S. villosum (P00055172), so we have used the flowering collection (Drège 7864b) at G-DC (G00144331) that is also the holotype of var. angustifolium as the lectotype of S. retroflexum, making the two names homotypic.
Solanum burbankii was described from living material sent to Bitter ("colui ipso in horto Bremeno complures per annos e seminibus ab horto Hamburgensi acceptis" [grew in the Bremen garden for several years from seeds originally accepted from Hamburg]) and thought to have been from California (Bitter 1913b) and thus, perhaps, from Luther Burbank himself. Bitter (1913b) cites no herbarium specimens in the protologue; if they were in either Bremen or Berlin, they were destroyed during the Second World War and we have found no specimens in Göttingen where some small fragments of collections are found (Vorontsova and Knapp 2010). From the description of a somewhat pubescent plant ("utrinque sparsim breviter pilosa") with pruinose berries with no stone cells, in which the calyx lobes are strongly reflexed at fruit maturity, we are certain Bitter is describing a sparsely pubescent form of S. retroflexum. We have selected a neotype for S. burbankii from specimens grown in St. Louis, Missouri that were obtained from the original distributor of Burbank's "wonderberry" seeds, J.L. Childs of New York. These specimens are almost certainly amongst those seen by William Trelease during his part in the newspaper war that was waged over the identity of the "wonderberry" in the early part of the 19 th century (see Heiser 1969) and match the description well. Several collections grown in Mr. Waldstein's garden are held at MO and we have chosen the sheet with the best fruiting material as the neotype.
The Swiss botanist Rudolf Probst worked extensively on the adventive flora found around woollen mills in Solothurn (Switzerland) and sent much of his Solanum material to the Hungarian botanist Sandor Polgár, apparently both as specimens and as seeds. In his various publications (Probst 1928(Probst , 1938, he quoted verbatim from Polgár's letters, attributing both names and descriptions to Polgár for S. nigrum var. probstii and S. burbankii var. glabrescens. The numbers he cites in the protologues apparently refer to years of collection (e.g. "22, 24, 26, 27"), but we are not certain; because of the labels on specimens in BP seen and annotated by Polgár, we are assuming Probst sent herbarium specimens rather than seeds. We are therefore considering this material as lectotypes for these two names, both of which correspond to S. retroflexum. The letter quoted verbatim in the protologue of S. nigrum var. probstii is mounted on a sheet with a collection date (29 Jul 1929) later than the description, so we select another Probst collection from 24 Aug 1926 and annotated by Polgár (BP acc. # 485285) as the lectotype for this name. The specimen collected by Probst on 20 Oct 1922 (BP acc. # 485327) has elements of the text repeated in the protologue attached to it and we designate this as the lectotype for S. burbankii var. glabrescens. 14. Solanum sarrachoides Sendtn., Fl. Bras. (Martius) 10: 18, tab. 1, fig. 1-8 Description. Annual erect to decumbent herbs 30-70 cm tall, rarely to 1 m, somewhat branching at base. Stems sprawling, terete, green, not markedly hollow; new growth densely viscid-pubescent with simple, spreading, uniseriate, translucent, glandular trichomes, the trichomes of two lengths, the shorter 1-4-celled, 0.2-0.5 mm long and the longer 5-14-celled, 1-2 mm long, both with glandular apical cells; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, 3.0-7.5 cm long, 3.0-6.0 cm wide, broadly ovate, thin and membranous, concolorous, without smell; adaxial and abaxial surfaces sparsely to densely pubescent with spreading, simple, uniseriate glandular trichomes like those of the stem, evenly distributed on lamina and veins; major veins 3-4 pairs; base truncate to cordate, sometimes asymmetric; margins entire or regularly sinuate-dentate; apex acute; petioles 0.5-3.2 cm long, sparsely pubescent with trichomes like those of the stem and leaves. Inflorescences 0.7-1.7 cm long, usually leaf-opposed but occasionally internodal, simple, sub-umbelliform, with 2-5(-7) flowers clustered at the tip, sparsely pubescent with spreading trichomes like those of the stems; peduncle 0.7-1.0 cm long, straight; pedicels 5-7 mm long, 0.1-0.2 mm in diameter at the base, 0.3-0.4 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 0(-1) mm apart. Buds globose, the corolla included within the calyx lobes and only the tip of the bud showing. Flowers 5-merous, all perfect. Calyx tube 0.5-1.0 mm long, conical, the lobes 1.5-2.0 mm long, 0.5-0.7 mm wide, lanceolate to narrowly ovate with acute  apices, sparsely pubescent with 1-4-celled spreading glandular trichomes like those on the pedicels but shorter. Corolla 5-8 mm in diameter, white with a yellow-green central eye, pentagonal-stellate, lobed 1/2-1/3 of the way to the base, the lobes 3.0-4.5 mm long, 5.0-7.0 mm wide, spreading at anthesis, sparsely papillate-pubescent abaxially with glandular 1-4-celled simple uniseriate trichomes and eglandular papillae, the denser along margins, tips and midvein. Stamens equal; filament tube minute; free portion of the filaments 1.0-1.5 mm long, adaxially sparsely pubescent with tangled uniseriate 4-6-celled simple trichomes; anthers 1.2-2.0 mm long, 0.4-0.8 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style 3.0-3.5 mm long, densely pubescent with 2-3-celled simple uniseriate trichomes in the lower 1/2-2/3 where included in the anther cone, not usually exserted beyond the anther cone; stigma capitate, minutely papillate, green in live plants. Fruit a globose berry, 6-9 mm in diameter, green-brownish grey at maturity, the pericarp thin and dull to somewhat shiny; fruiting pedicels 5-9 mm long, 0.2-0.3 mm in diameter at the base and at the apex, spaced 0-1 mm apart, reflexed, dropping with mature fruits, not persistent; fruiting calyx accrescent, becoming papery in mature fruit, the tube 3-4 mm long, the lobes 5.5-8.0 mm long and 3.5-4.0 mm wide, the tips slightly reflexed or spreading. Seeds (23-)59-69(-93) per berry, 1.3-1.7 mm long, 1.0-1.5 mm wide, flattened and tear-drop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells 4-6 per berry, (0.5) 0.8-1 mm in diameter. Chromosome number: 2n=2x=24 (Edmonds 1972(Edmonds , 1977Bukenya 1996;Moyetta et al. 2013;Olet et al. 2015).
Distribution (Figure 45). Native to southern South America, but has been introduced globally as an agricultural weed.
Ecology. Grows in urban areas, along riversides and other disturbed areas; between sea level and 2,300 m elevation in its native range, between sea level and 800 (1,400) m in the introduced range.
Uses. None recorded. Preliminary conservation status (IUCN 2016). Solanum sarrachoides is not a weedy species and has not spread far despite various introductions across the world; in its native range, it is widespread (EOO 2,089,288 km 2 ) and can be assigned a preliminary status of LC (Least Concern; Table 7).
Discussion. Solanum sarrachoides is morphologically similar to S. nitidibaccatum. The two taxa can be distinguished based on generally truncate leaf bases, leaf-opposed inflorescences that are umbellate to sub-umbellate with fewer flowers (2-5, rarely 6-7), shorter calyx lobes 1.5-2.0 mm long and a corolla with yellow-green central eye in S. sarrachoides, compared to S. nitidibaccatum which has attenuate to cuneate leaf bases, internodal inflorescences that are racemose with more flowers (4-8, occasionally up to 9-10), longer calyx lobes 1.7-2.5 mm long and a corolla with yellow-green central eye with black-purple "V"or "U"-shaped margins. The buds of S. sarrachoides are included in the calyx until just before anthesis and the berries are usually matte instead of shiny as they are in S. nitidibaccatum.
Solanum sarrachoides is a diploid species native to north-eastern and central Argentina, Paraguay and southernmost Brazil. The introduction of the species to Europe and North America is largely due to trade with South America and the importation of seeds and grain together with the practice of spreading wool waste ('shoddy') as manure and, based on herbarium records, seems to have been introduced some time at the beginning of the 20 th century. Despite its introduction in the early 1900s, the species remains relatively uncommon in both Europe and North America, with sporadic records from elsewhere, including South Africa (e.g. Eastern Cape, Phillipson & Hobson 5256). Solanum sarrachoides has not spread to Australasia; all literature records (e.g. Healy 1974;Henderson 1974;Ogg et al. 1981;Schilling 1981;Symon 1981) suggest that material from Australasia refers to material we recognise as S. nitidibaccatum.
Within the Old World, S. sarrachoides has often been confused with S. nitidibaccatum and records of S. sarrachoides or S. nitidibaccatum in literature should be taken with caution due to common misidentification of voucher material. Many regional treatments do not separate between these morphologically very similar species (e.g. Stebbins and Paddock 1949). Edmonds (1986) provides a discussion of the complex synonymy and lectotypification of S. sarrachoides. The species epithet is often seen spelled as "sarachoides", because Sendtner was thought to have named this species after the genus Saracha Ruiz & Pav.
Distribution (Figure 48). Native to tropical Africa, but introduced worldwide as a cultivated plant.

Ecology.
Grows in open areas, in a wide variety of habitats, in wet forests or drier areas, along roads and at field edges; often cultivated; between sea level and 2,300 m elevation.
Uses. Leaves used as greens (spinach) and cooked, sold in markets; berries used as ink; in Benin, the powdered leaves are used to cure dysentery (Essou and Hermans 2006). (IUCN 2016). Solanum scabrum is widespread across Africa and an important leafy vegetable in cultivation; it can be assigned a preliminary status of LC (Least Concern; Table 7), but it may become important to conserve local populations in order to preserve genetic variation for plant breeding.

Preliminary conservation status
Discussion. Solanum scabrum is the most commonly cultivated and widespread of the African black nightshades. It is the most important indigenous leafy vegetable in the black nightshade group and is commonly known as the African nightshade (Edmonds and Chweya 1997;Dinssa et al. 2016). Solanum scabrum shows great variation in growth form, leaf shape and size and berry number, in part due to the significant local variation introduced by human selection in cultivated populations.
The species has also been introduced to Europe, North America, Australia and New Zealand. In the United States of America, S. scabrum is known as "Garden Huckleberry" and its identity, origin and suitability to human consumption were the subject of great interest in the 1960s (as S. guineense, e.g. Heiser 1959, 1961;Heiser 1969).
Different cultivars are recognised, the late flowering plants cultivated for their larger abundance of leaves with smaller number of fruits and earlier flowering plants that have larger inflorescences which are cultivated for their fruits (Manoko 2007). Cultivated forms of S. scabrum stand out as quite distinctive; all forms have larger flowers and anthers that are often brownish in colour, while the forms cultivated for their leaves have larger, longer petiolate leaves and those cultivated for their fruits have larger, more numerous and shinier berries (the size of cherries) on erect or spreading pedicels. The pericarp in S. scabrum berries in all varieties is quite thick compared to other black nightshades, but mature berries of cultivars show variation in anthocyanin content where some individuals have dark purple mesocarp and others pale green. One of the major limitations to cultivation of S. scabrum as a leaf vegetable is the relatively low leaf yield due to early flowering and excessive fruiting Ojiewo et al. 2006). In response to this, enhanced varieties are being developed and new registered varieties are being released (Ojiewo et al. 2006;Ojiewo et al. 2013) such as "Medium leaf long-lasting" released in Kenya in 2006. Breeding is also focussing on local variation and drought resistance (Dinssa et al. 2016).
The presumed wild forms were described at the infraspecific rank by Olet et al. (2006) as subsp. laevis. This differs from the cultivated forms in having narrower leaves and smaller fruits that are globose rather than subglobose. Dehmer (2001) and Olet et al. (2011) have shown, however, that these differences are not reflected in relationships based on AFLP molecular markers. These wild forms of S. scabrum have often been called S. nigrum (e.g. Edmonds 2006aEdmonds , 2006bEdmonds , 2012, but they differ from true S. nigrum which, in Africa only occurs in the north along the Mediterranean, in their congested inflorescences, spreading pedicels, calyx lobes that tear unevenly and longpetiolate leaves. Olet et al. (2011) clearly demonstrated that the wild forms of S. scabrum are genetically closely related with cultivated S. scabrum accessions and form a distinct cluster away from European S. nigrum.
Solanum scabrum can be distinguished from the somewhat similar S. americanum by its larger anthers (2-3 mm long versus 0.8-1.5 mm long). In both these species, as well as S. retroflexum, the berries usually lack stone cells (some populations of S. americanum can have up to 4 stone cells) and drop without the pedicels at maturity, leaving the pedicels behind on old inflorescences. In both S. scabrum and S. americanum, berries are purple-black and shiny, while S. retroflexum has dull purple-black berries with a distinct grey bloom. The pedicels of S. scabrum are usually erect or spreading.
Plants described as S. fistulosum and S. oleraceum var. macrocarpon by Dunal (1814, 1852 respectively, see synonymy) from Brazil were almost certainly taken there from western Africa by enslaved people and were either collected from home gardens or became established in the New world.
Solanum scabrum is closely related to S. nigrum and S. villosum based on molecular data (Manoko 2007;. The close relationship amongst these polyploids indicates that they might share the same diploid parent. The idea that S. villosum is the likely tetraploid parent of the hexaploids S. nigrum and S. scabrum has also been supported by evidence from crossing experiments and cytological studies (Soria and Heiser 1961;Heiser et al. 1965;Rao et al. 1971;Jardine and Edmonds 1974;Edmonds 1977Edmonds , 1978Edmonds and Glidewell 1977;Edmonds 1978). Two possibilities still remain: one of the hexaploid species (S. nigrum and S. scabrum) evolved first and gave rise to the other or that the two hexaploids originated from the same parents independently . These two scenarios will be difficult to distinguish based on molecular data due to the complexity caused by high ploidy level.
The nomenclature and typification of the various synonyms of S. scabrum and the earliest name applied to the taxon, have been extensively discussed by others (e.g. Gras 1863 ;Thellung 1927;Polgár 1939;Stebbins and Paddock 1949;Soria and Heiser 1959;Heine 1960;Edmonds 1979b). We merely add additional notes for our lectotypifications designated here or for those that have been designated inadvertently (e.g. Prado et al. 2015). Edmonds (2012) designated a specimen in the Dillenian herbarium at OXF as the lectotype for S. melanocerasum All.; Allioni did not cite and probably never saw these specimens; this is correctable to neotype. D'Arcy (1974a: 737) inadvertently lectotypifed S. guineense Lam. by citing a specimen in "Herb. Lam. s.n. (P)" as "Type"; this corresponds to a specimen in the Lamarck herbarium (P00357674) that is labelled "Solanum nigrum guineense L. planta glabra.. fructu magno nigro. Sol. guineense Lam. Ill", suggesting that Lamarck was basing his name on Linnaeus' S. nigrum var. guineense. In the protologue, Lamarck (1794) indirectly referred to Linnaeus, through citing the single element in the protologue of S. nigrum var. guineense, the illustration in Dillenius (1732). We are therefore treating these two names (S. nigrum var. guineense L. and S. guineense Lam.) as homotypic, rendering D'Arcy's (1974a) lectotypification superfluous.
Lamarck's (1794) S. triangulare has traditionally been considered a synonym of S. africanum Mill. (a member of the Dulcamaroid clade, Knapp 2013); the protologue cites two elements, only one of which "?" represents S. africanum and was questioned as only possibly being the same by Lamarck. The other cited element of S. triangulare is an illustration from Herbarium Amboinense (Rumphius 1750) that represents S. americanum. D'Arcy (1974a), however, cited the specimen in Lamarck's herbarium ("Lamarck s.n. (P)"; P00357626) as "Type" and we must accept this as a valid lectotypification. This specimen is of a narrow-leaved plant of S. scabrum.
Willdenow (1809) did not specifically reference Allioni's epithet in his protologue, so we are treating it as a new name. There is no material in the Willdenow herbarium labelled as S. melanocerasum, but a specimen (B-W04368010) of S. scabrum (labelled as "S. guineense" and "ex horto proprio W") was clearly grown in Berlin and seen by Willdenow. We designate this as the neotype for S. melanocerasum Willd.
Solanum pterocaulum is illegitimate because Dunal (1813) cited S. scabrum in synonymy. In the Prodromus (Dunal 1852), his use of 'pterocaulon' was simply an orthographic variant and is correctable (see McNeill et al.. 2012, Art. 61.5 and associated provisions in Art. 61); it does not alter the legitimacy of the name.
No original material has been traced for S. memphiticum Mart., but the emphasis placed on the dark purplish colour of the stems and leaves by Martius (1814) in the protologue, coupled with the petiolate nature of the leaves and the erect peduncles, suggests this plant was S. scabrum.
Of the several species in this group described by P.M. Opiz (see discussion under S. nigrum), we are convinced from the description that S. nitens is a synonym of S. scabrum, rather than of S. nigrum, although Opiz (1843) places it in his "superspecies" S. nigrum. The mention of shiny berries on erect pedicels is distinctive; we have yet to confirm this with specimens from Opiz's herbarium at PR.
The lectotype (G00144295) chosen for S. oleraceum var. macrocarpum is the better preserved of the two duplicates of Martius 1225 cited by Dunal (1852).
The lectotype chosen for S. tinctorium (Welwitsch 6103) is the more clearly duplicated of the collections cited in the protologue; we have selected the best preserved sheet (BM000942995) as the lectotype. The name apparently comes from the staining berries that were used as ink.
Selected specimens examined. Description. Annual to short lived erect to weakly scrambling perennials to 1.5 m tall, subwoody and somewhat branching at base. Stems spreading to decumbent, usually somewhat winged and with spinescent processes, fleshy, green to somewhat purple tinged, older stems drying pale yellowish-brown or whitish-grey, markedly hollow and even older stems collapsing in herbarium specimens; new growth glabrous or sparsely to moderately pubescent with simple, spreading, uniseriate, translucent, usually eglandular (sometimes tipped with a single-celled gland) trichomes, these 3-5-celled, 0.2-1.0 mm long; older stems glabrous. Sympodial units difoliate, the leaves usually not geminate. Leaves simple, 3-13 cm long, 1.5-2.5 cm wide, ovate to elliptic, very variable in size even on an individual plant, membranous, concolorous, without smell; adaxial surface glabrescent to sparsely pubescent with simple uniseriate trichomes like those on stem; abaxial surface usually less pubescent that the adaxial ones, glabrous to sparsely pubescent with simple uniseriate trichomes; major veins 4-8 pairs; base abruptly attenuate; margins entire or very rarely shallowly sinuate to lobed, if so the tips of the lobes acute or rounded; apex acute to attenuate; petioles (0-)4-8 cm long, pubescent with simple uniseriate trichomes like the leaves. Inflorescences 1-4(-6) cm long, internodal, unbranched or with up to 5 branches, but if branched usually only furcate, the flowers spaced along the rhachis, with 10-40 flowers, glabrous or sparsely pubescent like the stems; peduncle 1-3(14) cm long; pedicels 0.7-0.8 cm long, ca. 0.3 mm in diameter at the base, ca. 0.5 mm in diameter at the apex, slender, nodding at anthesis, sharply bent just above the insertion point so the base of the pedicel is an acute angle, this especially noticeable in fruit, articulated at the base or ca. 1 mm from the rhachis leaving a small stump, falling with the fruit at maturity; pedicel scars 1-2 mm apart in the distal part of the inflorescence, further apart towards the base. Buds ellipsoid, the corolla exserted ca. 1/2 way from the calyx until just before anthesis. Flowers 5-mer-  ous, perfect (although style length differs in flowers along the rhachis). Calyx tube ca. 1 mm long, conical with hyaline sinuses, the lobes 0.5-1 mm long, 0.4-0.9 mm wide, ovate to broadly triangular, glabrous to sparsely pubescent like the rest of the inflorescence. Corolla (6-)8-10 mm in diameter, white, stellate, lobed ca. 1/2 way to the base, the lobes 3-4 mm long, 1.5-2 mm wide, spreading or reflexed (apparently reflexed in older flowers), minutely papillate on the tips and margins. Stamens equal; filament tube ca. 0.25 mm long; free portion of the filaments 0.5-0.75 mmm long, adaxially pubescent with tangled simple uniseriate trichomes; anthers 1.5-2.5 mm long, 0.75-1 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary rounded, glabrous; style 3.5-5 mm long, bent or straight, densely pubescent in the basal 1/2 to 1/3, exserted to ca. 1 mm or occasionally included in the anther cone and the stigma flush with the pores; stigma capitate, the surface minutely papillate. Fruit a globose berry, 4-6 mm in diameter, pale green or translucent blackish-grey when ripe, the pericarp thin, matte; fruiting pedicels 0.8-1.1 cm long, ca. 1 mm in diameter at the base, sharply bent at the base and strongly pendent, dropping with mature fruits, not persistent; fruiting calyx not accrescent, the tube ca. 1 mm long, the lobes 0.5-1 mm long, appressed to the berry, the calyx from above pentagonal or stellate. Seeds 20-40 per berry, 1.5-2 mm long, 1-1.5 mm wide, flattened and tear-drop shaped with a subapical hilum, tan or pale brown, the surfaces minutely pitted, the testal cells elongate-rectangular. Stone cells (0-)1-5(-10) per berry. Chromosome number: 2n=4x=48 (Olet et al. 2015;Manoko 2007).
Distribution ( Figure 51). Common throughout sub-Saharan tropical Africa from Sudan to Mozambique and South Africa and west to Cameroon and Angola; we have also seen a few isolated collections from the Comoro Islands and Madagascar (perhaps introduced).
Ecology. Grows in a wide variety of disturbed habitats, along forest margins and roadsides and in clearings, often cultivated; between (0-) 500 and 3,300 m elevation. Uses. Leaves eaten as a vegetable throughout the range; also used as a medicinal plant (in Karamoja Distr., Uganda).
Preliminary conservation status (IUCN 2016). Solanum tarderemotum is widespread across tropical Africa and can be assigned a preliminary status of LC (Least Concern; Table 7).
Discussion. Solanum tarderemotum is a morphologically variable species. Edmonds (2012) recognised individuals with branched inflorescences as S. florulentum and applied S. tarderemotum only to material with simple inflorescences, but branched and simple inflorescences can occur on the same specimen, depending on age. Intermediate material was occasionally recognised in some accounts under the unpublished name "Solanum eldorettii" (Olet 2004;Manoko 2007). Crosses between the forms of S. tarderemotum (as S. tarderemotum A, B, and C, and S. florulentum) yielded the full range of phenotypes, including intermediate individuals and both "parental" phenotypes (Manoko 2007). Solanum tarderemotum is distinguished from other sympatric species by its usually many-flowered inflorescences, long-exserted style that often is bent rather than perfectly straight (easier to see in live plants), spathulate calyx lobes that are rounded at apex, very strongly reflexed fruiting pedicels and berries that drop with the pedicel attached. Stems of S. tarderemotum are hollow and collapse upon drying, unlike the stems of the similar S. villosum that are more solid. Solanum scabrum also has hollow stems, but fewer-flowered inflorescences and larger fruits that drop without the pedicels. Solanum nigrum (North African populations), S. scabrum and S. villosum all lack stone cells, while the fruits of S. tarderemotum consistently have 2-6 stone cells in each berry. Most material of S. tarderemotum is either glabrous or has eglandular pubescence, but plants from higher elevations in the eastern African mountains are glandular pubescent; these were identified as S. pseudospinosum by Edmonds (2012).
Previous molecular studies identified S. tarderemotum form C (Clade IV) as a separate entity based on AFLP data that was analysed using Maximum Parsimony phylogenetic method (Manoko 2007). Individuals clustering apart from the main clade of S. tarderemotum and S. florulentum (Clade IV) showed simple inflorescences with fewer flowers, narrower corolla lobes and green fragrant fruits at maturity distinct from majority of accessions of S. tarderemotum and S. florulentum (Manoko 2007). The results from the AFLP phylogeny are not, however, supported by sequence based molecular phylogeny based on both rapidly evolving non-coding plastid and low-copy nuclear markers (Särkinen et al. unpublished). The accession, on which S. tarderemotum form C (Clade IV) was based (NIJ 964750060), does not have locality or origin data and hence, we prefer assuming that the collection represents morphological variation of S. tarderemotum as circumscribed here, supported by molecular sequence data. The differing relationships in the AFLP phylogeny in Manoko (2007) could be explained by the general difficulty in interpreting AFLP banding patterns objectively in closely related species and highlight the issues in using AFLP data in phylogenetic analyses.
Solanum tarderemotum is a tetraploid species with unknown parentage (Olet et al. 2015). The species has not been included in any previous crossing and molecular studies that have focused on understanding the parental origin of the hexaploid species S. nigrum and S. scabrum (e.g. Edmonds 1977Edmonds , 1979aGanapathi and Rao 1985, 1986b, 1986c, 1987a, 1987bJacoby et al. 2003;Jacoby and Labuschagne 2006;van der Walt et al. 2008;. It could represent one of the tetraploid parents of the hexaploids and should be included in further studies focused on understanding the origin of the polyploids. Both names S. tarderemotum and S. florulentum were published in the same publication. No publication has yet synonymised the two. Most of the types for all names associated with our circumscription of this species were destroyed in Berlin. We have chosen to use the name S. tarderemotum because the holotype (WRSL) is still extant, while no known duplicates of the type of S. florulentum have been located.
Distribution (Figure 54). Native to the Americas with an amphitropical distribution between temperate South and North America. Introduced outside its native range in Europe, South Africa and Australia, probably with agricultural seed or wool waste.
Ecology. Grows across a wide range of habitats, along road sides, sandy soils, in cultivations and in salt plains; between sea level and 2,300 (-2,900) m elevation in its native range, between sea level and 1,800 m in the introduced range.
Uses. None recorded; a weed of agriculture. Preliminary conservation status (IUCN 2016). Solanum triflorum is a weedy species that is invasive where introduced; it has a large EOO and can be assigned a preliminary status of LC (Least Concern; Table 7). The EOO, based on native range only, is also very large (19,993,876 km 2 ), mainly due to the disjunct distribution between North America and southern South America.
Discussion. Solanum triflorum is a weed of agricultural areas and appears not to spread aggressively based on collection numbers (see Knapp 2018). It is easily distinguished from other species in the Old World by its usually deeply lobed leaves that are often pinnatifid, but are sometimes only shallowly lobed (see van Ooststroom 1966; description of var. dentatum), the usual presence of a bracteole in the inflorescence, very narrowly elliptic buds and berries with > 30 stone cells per berry.
In its native range, S. triflorum has a very large range of berry sizes; most introduced material has larger berries, but it is possible we have not seen material that has the smaller berry size from the Old World. There is also large variation in the indumentum and leaf shape in S. triflorum in its native range (Subils 1989), some of which can be seen in the Old World material. This variation is likely caused by environmental factors and has no taxonomic relevance (Subils 1989).
Distribution (Figure 56). Endemic to the southern highlands of Tanzania. Ecology. Grows on volcanic soils, frequent on the ash layer in charcoal-burning areas, also commonly cultivated; between 1,700 and 2,200 m elevation.
Common names. Tanzania: insungwe [Malila people] (Schippers 2000). Uses. Leaves used as spinach; berries eaten raw. Preliminary conservation status (IUCN 2016). Solanum umalilaense is known mostly from cultivation in the southern part of Tanzania; based on its range (EOO = 2,559 km 2 ; EN) and the number of populations (AOO = 32 km 2 ), it would be assigned a preliminary conservation status of EN (Endangered), but might be better considered DD (Data Deficient). It is protected by local people and its range is poorly known. Discussion. Solanum umalilaense can be distinguished from other African species of morelloids by its simple to branched and often leafy inflorescences, flowers with very short rounded calyx lobes and persistent, small, light yellowish-brown fruits. Solanum umalilaense produces a large number of inflorescences such that, at full anthesis, the plant appears to be covered with white flowers, strikingly different from other species in the section (Manoko et al. 2012), except some populations of S. tarderemotum (the branched-inflorescence form previously recognised as S. florulentum). Like S. tarderemotum, the berries fall with the pedicels still attached. Manoko (2007) used AFLP molecular markers to assess the relationships of the tetraploid African species and found that S. umalilaense (as "Sp. A") was a member of a cluster including S. retroflexum (as S. hirsutum (Vahl) Dunal and S. retroflexum) that itself clustered with S. tarderemotum.

Solanum villosum
Distribution (Figure 59). Native to the northern Hemisphere, from Europe, especially around the Mediterranean basin, Arabian Peninsula to dry sub-tropical Asia and eastern Africa (where it is cultivated for its fruit); introduced globally. The native distribution of S. villosum is restricted to the Old World, but cultivated and/or introduced populations that never seem to persist are occasionally found in North America and the Caribbean (Stebbins and Paddock 1949).
Ecology. Grows in open and disturbed areas in a wide variety of habitat types, including in cities; between sea level and 3,000 (-3,600) m elevation.
Uses. Leaves used as spinach (usually boiled, often in milk) and as a pot-herb in Europe, Africa and the Middle East; berries eaten raw (especially by children, see Uses above) and cooked (Pojarkova 1955a, b). Medicinal uses include treatment of eye conditions and swellings (see Yang and Ojiewo 2013).
Preliminary conservation status (IUCN 2016). Solanum villosum is a very widespread species and can be assigned a preliminary status of LC (Least Concern).
Discussion. This common European species was long known as S. luteum (e.g. Hawkes and Edmonds 1972) and this name was in wide use in botanical gardens as the name for this red-fruited taxon. The name S. villosum Lam. was recognised as a synonym for S. luteum. The name S. villosum Mill. was not in use in Europe until resurrected by Edmonds (1979b), but had been used by Stebbins and Paddock (1949) in their treatment of the morelloids of California. Edmonds (1979b), following what is now Article 11.5 of the Code , changed the name to S. villosum Mill. citing the explicit synonymisation of S. luteum with S. villosum Mill. by Stebbins and Paddock (1949). Dostál (1949), only a month later than Stebbins and Paddock (1949), synonymised S. villosum with S. luteum, but unfortunately used the name in the Lamarckian sense, although in a letter to Edmonds (quoted in Edmonds 1979b) equated S. villosum Mill. and S. villosum Lam. Many specimens in European herbaria are still identified as S. luteum or as S. alatum (see Knapp et al. 2017 for discussion of S. alatum).
Variation in pubescence and stem characteristics within S. villosum has been recognised at many ranks from subspecies, varieties and different species (Hawkes and Edmonds 1972;Edmonds 1979bEdmonds , 1984bHenderson 1974;Symon 1981;Edmonds and Chweya 1997;Olet 2004;Dehmer and Hammer 2004). The various synonyms and infraspecific ranks reflect the wide morphological variation observed within the species, where indumentum can range from nearly absent (the plants glabrous) to densely pubescent with eglandular and/or eglandular trichomes. The recognition of the glandular variants at infraspecific rank is not supported by AFLP data (Manoko 2007;Olet et al. 2011). In fact, studies have shown that pubescence varies in individuals according to age, where seedlings can exhibit glandular hairs which are lost during growth (Henderson 1974;Seithe 1979;Edmonds 1982). Here we have an inclusive, broad concept of S. villosum that includes this variability but does not recognise it at any rank.
Solanum villosum can be easily recognised from similar species by its orange-red berries (ranging from yellow to bright red) that are slightly elongate and ellipsoid. The only other species present in the Old World with pale yellow fruits is S. palitans, but this taxon differs in being a prostrate plant with thinly membranous 3-lobed leaves and is easy to tell apart. The rest of the morelloids in the Old World have rounded or subglobose black or green berries. Solanum villosum is much more common in southern Europe than is S. nigrum, while S. nigrum becomes more common towards northern and central Europe. These latter two species are difficult to tell apart based on herbarium material alone, especially when mature fruit colour is not available. Calyx lobes of S. villosum are generally longer than those of S. nigrum (relative to width), strongly reflexed at fruit maturity and the sinus is rounded (as opposed to acute in S. nigrum) and, in flower, the calyx tube has pale patches that look like small windows or white/ translucent areas below the sinus itself. This is particularly easy to see in herbarium specimens. The leaves of S. villosum are similar to those of S. retroflexum in being usually more or less rhomboid with dentate margins, but leaves are more narrowly rhomboid than those of S. retroflexum (i.e. narrower relative to length). Specimens from the southern part of the range of S. villosum and the northern range of S. retroflexum (e.g. Malawi and Mozambique) can be difficult to distinguish in the absence of information on fruit colour (S. retroflexum has dull purple-black berries, also with strongly reflexed calyx lobes in fruit).
Solanum villosum has generally distinctly longer filaments relative to anther length than other species (except S. opacum and S. retroflexum, see descriptions of these species), although large variation can be observed within and between individuals especially in herbarium specimens. We have observed in the field that filaments elongate during flower maturation, where younger flowers in the same inflorescence can be seen with shorter filaments and older flowers with fully extended and distinctly longer filaments (SK photo 101532). Solanum villosum has a large capitate stigma that does not generally extend much beyond the anthers, in contrast to S. tarderemotum with which it often grows in sympatry in Africa, where the style is long-exserted and often bent and the stigma is smaller.
A set of herbarium and seed bank accessions of S. villosum from Kenya have narrower leaves with entire margins and larger, branched inflorescences with fruits in which calyx lobes do not recurve as strongly as in more typical populations, but that lack stone cells in the berries. These accessions are somewhat morphologically intermediate between S. villosum and S. tarderemotum and could present man-made or natural introgression between the two species (see discussion of S. tarderemotum).
The origin of the tetraploid S. villosum has been the focus of previous crossing and cytological studies (e.g. Edmonds 1979a). Molecular , experimental breeding (Tandon andRao 1966a, 1966b;Venkateswarlu and Rao 1972;Rao 1978) and chromosome binding data (Bhiravamurty and Rethy 1984;Sultana and Alam 2007) suggest that the species is an ancient autopolyploid with regular bivalent formation derived from S. americanum. Edmonds (1979a) suggested that S. villosum is derived from the diploid parents S. americanum and S. sarrachoides, because these two diploids are interfertile. The hypothesis in which a native of the New World, S. sarrachoides, would have given rise to an Old World endemic is not particularly convincing, but current distributions of progenitor taxa do not necessarily have to overlap (e.g. Nicotiana tabacum L., see Chase et al. 2003). The autopolyploid origin of S. villosum and its contribution to the autoalloploid S. nigrum derived from S. villosum and S. americanum, is more likely, considering their sympatry across the entire range of S. villosum. Furthermore, S. sarrachoides is reproductively isolated from all other diploids studied thus far (Edmonds 1977), making it less likely that the species has been involved in allopolyploidy. A possible diploid progenitor could be S. chenopodioides, however, as suggested by Edmonds (1979a), with which S. nigrum and S. villosum share some of their distributions. It is much more likely, however, based on the current molecular, morphological, artificial crossing and cytological studies that S. nigrum is an autoallopolyploid derived from a genome duplication of the tetraploid S. villosum that comprises genomes of two distinct populations of S. americanum. Morphological characters support this, in that S. americanum and S. villosum both drop their fruits without pedicels. Edmonds (1979b) superfluously lectotypified S. nigrum var. villosum with a specimen in the Linnean herbarium (LINN 248.19), apparently not realising the name had already been lectotypified completely in accordance with the protologue by Henderson (1974), using the illustration from Hortus Elthamensis (Dillenius 1732;see Jarvis 2007). named this species S. incanum, but there is already one in the Flora Peruviana, so I name it after my esteemed friend, who found it first in Hungary). Edmonds (1979b) cited specimens as holotypes for these names, effectively lectotypifying them. She cited a specimen in the Willdenow herbarium (B-W04421010) as the "holotype" of S. flavum; it is more likely however, that Schultes used specimens now held in M (Schultes's herbarium at Landshuth, where he worked at the time of description of these two taxa and this is now part of M). The lectotype for S. kitaibelii has the name in Schultes's hand (M-0166013), but the isolectotype for S. flavum does not (M-0164200).
We have designated a specimen with the exact locality as the lectotype of S. ochroleucum; the G-DC duplicate is better preserved (G00144474).
Döll's various infraspecific taxa described in his Rheinische Flora (1843) as "Formen" (here taken as the rank of forma) are mostly new combinations of previously published epithets, but his forma angulosum is based on several cited localities in Germany. We have not been able to locate specimens for these collections and defer typification until more in-depth searches are done. It may be that these names are based on field observations and not herbarium material.
Solanum sinaicum was described by Boissier (1849) using a collection of his own from Arabia; he did not cite a herbarium, so we are lectotypifying this name with a specimen in G (G00343377). Although the protologue mentions "baccis nigricantibus", the plants are unmistakably S. villosum; we suspect the fruit colour was cited from the dry specimen.
The spelling of Richard's (1850) name S. plebeium has sometimes been corrected to "plebejum" (e.g. Edmonds 2012). This is not necessary and incorrect, "plebeium is the nominative neuter singular of "plebeius", meaning "commoner" or "of the common people". Dunal (1852) described three varieties of S. miniatum; var. villosissimum and var. stenopetalum based on European specimens and var. subserratum based on a specimen from "Arabia". Edmonds (1979b) discussed the identities of these varieties, but did not typify them. Dunal cited the same collection Castagne s.n. from "Montaud prope Salon" for both var. stenopetalum and var. villosissimum; we have lectotypifed var. villosissimum with the other specimen cited that does not overlap with that used for var. stenopetalum (G00144520). Material in Dunal's herbarium at MPU (MPU091757), labelled as "Arabie" and cited by Edmonds (1979b), is labelled as var. villosissimum and numbered "No. 26" and is undoubtedly original material of var. subserratum. This sheet is here designated the lectotype for this name, despite its having an annotation label with the incorrect infraspecific name. In describing S. minutiflorum, he (Dunal 1852) cited two collections "Pannonia circa Bannat -(Terenbinki l.c.)" and a specimen from Richard. We have chosen the latter as the lectotype because it has two duplicates; neither Edmonds (1979b) nor we were able to locate the other syntype.
The names coined by the Hungarian botanist Pál Kitaibel were published posthumously by Kanitz (1863) and are largely illegitimate (some were used in earlier publications by Schultes, see above). Solanum flavum and S. canescens were published as alternative names "Solanum flavum vel canescens" and therefore have the same type; we have selected the sheet in the Kitaibel herbarium at BP with the locality on the label Solanum nodiflorum Jacq. var. sativum A.Chev. Expl. Bot. Afrique Occ. Franç. 1: 464. 1920. nomen nudum; based on "Guinea. Kankan, dans les jardins cultives, 16 Mar 1899, A.Chevalier 594" = S. scabrum Mill. Solanum pigmaeum Larrañaga, Escritos Damaso Antonio Larrañaga 2: 88. 1923, almost certainly not intended as a new name, an orthographic variant of Solanum pygmaeum Cav. (1806). In other parts of Larrañaga's work (e.g. S. trilobum in vol. 1: 12), he indicates new taxa with "sp. n." or gen. n."; none of the names in vol. 2 is so designated, leading us to believe he was not coining new names, but instead using those already published. This work was compiled from his notes and diaries and these were heavily annotated (see intro in vol.