Research Article |
Corresponding author: Carol A. Wilson ( cawilson@berkeley.edu ) Academic editor: Lorenzo Peruzzi
© 2020 Carol A. Wilson.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wilson CA (2020) Two new species in Iris series Chinenses (Iridaceae) from south-central China. PhytoKeys 161: 41-60. https://doi.org/10.3897/phytokeys.161.55483
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Iris dabashanensis C.A.Wilson, sp. nov. and I. probstii C.A.Wilson, sp. nov. from China are described and illustrated. Both species occur on grassy slopes in mountainous regions of south-central China. The former is known from the Daba Mountains in rocky, calcareous soils associated with shrubs or mixed conifer and hardwood forests, while the latter is known from a region of karst terrain beside rice fields or under pine woods in Guizhou Province. Molecular data resolves both species in series Chinenses in a subclade that also includes I. odaesanensis, while morphologically they are similar to I. henryi. These newly described species are two of four members of series Chinenses that occur in south-central China.
Daba Mountains, Guizhou Province, karst terrain, phylogeny
Iris series Chinenses G.H.M. Lawr. comprises several Asian species that have short rhizomes, stolons, and small, open flowers where petals and sepals are horizontal.
Taxonomic treatments of Iris series Chinenses.
Species |
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I. cavaleriei H.Lév. | Synonym of I. grijsi | Not included | Not included | Not included |
I. gracilipes Pamp. | Not yet described | Not included | Not included | Synonym of I. henryi |
I. grijsi Maxim. | Chinese group | Series Chinenses | Synonym of I. speculatrix | Synonym of I. speculatrix |
I. henryi Baker | Chinese group | Series Chinenses | Series Chinenses | Series Chinenses |
I. koreana Nakai | Not yet described | Series Chinenses | Series Chinenses | Series Chinenses |
I. minutoaurea Makino | Chinese group | Series Chinenses | Series Chinenses | Series Chinenses |
I. odaesanensis Y.N.Lee | Not yet described | Not yet described | Series Chinenses | Series Chinenses |
I. proantha Diels | Not yet described | Not included | Sect. Lophiris Tausch | Series Chinenses |
I. rossii Baker | Chinese group | Series Chinenses | Series Chinenses | Series Chinenses |
I. speculatrix Hance | Section Evansia (Alef.) Baker | Subsect. Evansia Benth. | Series Chinenses | Series Chinenses |
Based on molecular studies (
In 2003, Darrell Probst collected one of the new species, I. probstii, at two sites in its native habitat in Guizhou Province and considered its flowers different from other species known from China. He sent materials of these plants to the author for further study. During this study it became apparent that the type specimen for I. henryi that was collected by Augustine Henry in 1885 and its description by
This study was undertaken to access the status of these two new species. The first goal was to determine morphological similarities and differences among these two new species, I. dabashanensis and I. probstii, and other species in series Chinenses. A second goal was to determine if species synonymized in I. speculatrix (I. cavaleriei and I. grijsi) are morphologically similar to I. speculatrix and distinct from each of the two new species. A third goal was to study materials of I. henryi and its illegitimate synonym, I. gracilipes Pamp., to determine if these two taxa are morphologically similar. Iris gracilipes Pamp. is illegitimate because the name was previously used by Asa Gray for a different species of Iris that is in section Lophiris Tausch (
Living specimens and vouchers of the two new species were examined and compared with each other. They were also compared to other species using descriptions, herbarium specimens, and images of herbarium specimens, focusing on species that occur in southern China and I. odaesanensis, a species resolved with molecular data in the same subclade as the two new species (Fig.
Genomic DNA of the new species, I. probstii, was isolated from silica-dried leaf materials using protocols modified from the CTAB method of
Geneious 9.1.4 (Biomatters Ltd., Auckland, New Zealand) was used to assemble the generated sequence reads into loci, concatenate loci by species, and align the final dataset. Equivocal nucleotide sites were coded according to the IUPAC (IUB) codes. Maximum likelihood (ML;
Collection sites of specimens representing the two new species were located on Google Earth Pro vers. 7.3.2.5776 (Google LLC, Menlo Park, California, U.S.A.) to determine the known range of each species. Maps were produced in QGIS vers. 2.18.13 (
The data underpinning the analyses reported in this paper are deposited in the Dryad Digital Repository at: https://doi.org/10.6078/D1C695
The two new species are morphologically most similar to I. henryi but differ in several characters as described below in the new species’ diagnoses. The two new species and I. henryi share several characteristics that distinguish them from I. cavaleriei, I. grijsi, and I. speculatrix, including smaller flowers, slender rhizomes that are also short, and long slender pedicels that result in exerted flowers and ovaries. The two new species and I. henryi also lack reduced basal leaves that are present in I. cavaleriei and I. grijsi. Iris proantha differs morphologically from the new species and I. henryi in several characters, including slightly larger flowers, longer floral tubes, and pedicels that are shorter and wider. Pedicels in I. proantha are more similar to those in I. cavaleriei, I. grijsi, and I. speculatrix than to the new species or I. henryi. Collections from the Daba Mountains and identified as I. henryi were determined to represent the new species, I. dabashanensis. Recent descriptions of I. henryi either fit I. dabashanensis (
Phylogenetic studies resolved the two new species in series Chinenses in a clade comprised of the new species + I. odaesanensis (Fig.
Study of specimens and type descriptions revealed morphological differences among I. cavaleriei, I. grijsi, and I. speculatrix. The former two taxa are considered synonyms of I. speculatrix. Each of these three taxa are distinct from the two new species because they lack the long pedicels, and short floral tubes present in I. dabashanensis and I. probstii and have larger flowers and rhizomes than species in series Chinenses. Notes from examination of the I. cavaleriei holotype deposited at the Royal Botanic Garden Edinburgh (E) describes a plant with basal leaves that are 0.3 cm in width with two veins, unequal lower bracts (9 and 12 cm), flower exerted above bracts, ovary hidden by bracts, sepals that are ca. 2.5 cm long x 0.4 wide, and reduced leaves around the base of the flower stem. Photographs taken at E show an ovary enclosed in bracts with the visible portion of the floral tube greater than 1 cm. A more precise description of the floral tube requires re-examination of the type because this measurement was not included in notes taken at E and
Comparisons between descriptions and herbarium sheets of I. gracilipes Pamp. and I. henryi did not reveal differences between these two species supporting the inclusion of the illegitimately named I. gracilipes Pamp. within I. henryi. However, it is possible that there are differences between these two taxa that are not evident in the known collections of I. gracilipes Pamp. These collections were made by Reverend Père Cipriano Silvestri in the early 1900s in northwestern Hubei Province. The type location of I. henryi is in central Hubei Province from the area of Liantuo (Nanto) west of Ichang (Yichang). Future fieldwork in the region of Silvestri’s collections and the type location of I. henryi is planned to further investigate these taxa. Iris henryi was not located during fieldwork by a colleague in 2019 west of Yichang, leading to concern that the type location may have been lost with development of the Three Gorges Dam on the Yangtze River.
No additional collections of the new species from Guizhou Province, I. probstii, were identified during study of herbarium specimens and images of specimens, although three specimens from Guizhou Province were examined. One specimen identified as I. speculatrix was collected in 2013 and deposited at the Guizhou Academy of Sciences (HGAS; 123147). Two specimens identified as I. grijsi were collected in 1898 and 1900 and deposited at the Muséum National d’Histoire (P; 01840535 and 0184536, respectively). Study of the image of the former specimen revealed that it fit the description and type of I. speculatrix. Images of the two specimens identified as I. grijsi were also studied and are most similar to other collections of I. grijsi. Specimen 01840535 is particularly informative, although a scale was not included when imaged. This specimen illustrates the short leaves at the base of the plant that are typical for this taxon and the longer bracts when compared to I. speculatrix.
The study of herbarium records revealed 34 additional specimens from the Daba Mountains that are the new species, I. dabashanensis, but were identified as other species. These represent sheets from nine separate collections from the Chongqing Municipality and one from the Shennongjia Forest Region in Hubei Province. Three botanists, Père Paul Guillaume Farges in 1892, Tain Lun Dai in 1958, and Du Wei in 2014 made these collections. Eight of the collections were identified as I. henryi while the 2014 collection was identified as I. proantha. It is not surprising that these collections were mostly identified as I. henryi because I. dabashanensis is similar to this species and in particular has long slender pedicels and flowering stems that are shorter than leaves at flowering, two characters considered distinguishing for I. henryi. A few other collections from near the Daba Mountains may also represent I. dabashanensis but a determination could not be made because flowers were lacking or important characters were not clearly visible.
The aligned, combined dataset was 3,551 bp with 398 (11%) variable and 153 (4%) potentially parsimony informative characters. The matK/trnK marker was more informative than trnL–F because it contributed 2,696 bp with 322 variable and 114 potentially parsimony informative characters. The resulting models from RAxML and MrBayes analyses differed only slightly in the three substitution rate and gamma distribution values (the numbers given are based on RAxML). Both assumed unequal base frequencies, three substitution rates (1.0000, 2.8325, 0.1513), a gamma distribution of 0.5726 and 0.3177 invariable sites. The single ML tree from RAxML and the consensus tree from MrBayes each had a log likelihood = -7,779 and shared the same topology (Fig.
The two new species were resolved with high support in a clade with I. odaesanensis. As described above, these three species share several morphological characters, including long slender pedicels and short floral tubes. They were resolved with high support within the series Chinenses clade and share several characters with other species in the series, including small, horizontally spreading flowers where petals are not upright, an overall small and delicate stature, short rhizomes, and an Asian distribution. All taxa in series Chinenses, except I. henryi, the nominative form of I. proantha, and I. rossii, were included in this study. Further studies to resolve relationships within the series should include these three taxa and also I. grijsi, I. cavaleriei, and I. speculatrix. The former two taxa are considered synonyms of I. speculatrix but in this study were shown as morphologically distinct. The type locality for I. henryi is not precise and the species has not been relocated in the area of its initial discovery.
The study also resulted in the discovery of two type collections and one correction to a species description citation. The type of I. speculatrix (C. Ford 18465) was discovered in BM collections stored as a type of I. henryi and the type of I. grijsi (de Grijs 8583) in P collections but not designated as a type. The description of I. cavaleriei is typically cited as Liliac. & C. Chine 18 1905, but previous searches for this journal were not successful. During this study the author searched journals where Augustin Abel Hector Léveillé published species descriptions, focusing on journals where he published infrequently. The correct citation is given in the references (
Morphologically similar to I. henryi the new species differs in having narrower leaves (0.9–2 mm versus 4–4.5 mm), shorter bracts (2–4 cm versus 4–7 cm), and shorter style branches (1 cm versus 1.8 cm).
China. Sichuan Province: About 5 km N of Wanyuan, Wanyuan County, 1,140 m, 32°11.720'N, 108°05.310'E, 3, May 2001 (fl), voucher from cultivated material, D. Probst CPC3.5.01.3 (holotype: UC!; isotypes: PE!, E!).
Small evergreen herbaceous plant with aerial flowering stems less than basal leaves. Bracts, cauline leaves, base of basal leaves ± tinged with red. Rhizomes short and branched with fibrous leaf remains. Stolons present. Roots slender, branched, with tubers to 6 mm. Basal leaves distichous, linear with acute apex, bright green, slightly glossy, 28–44 cm long, 0.9–2 (3) mm wide, 1–2 veins; crowded in clumps. Flowering stem ca. 8–18 cm with 1 or 2 cauline leaves, with upper cauline leaf extending well above mid stem. Inflorescence with two opposite bracts (spathes) subtending 2 (3) flowers, terminal flower opening first with a single bract subtending each subsequent flower; lower bracts ± equal, 2.0–4 cm long, 0.4–0.5 cm wide; pedicels long (2.5–5 cm) and slender. Flowers light violet, open, ca. 3 cm diameter, radial with petals slightly angled upward, sepals light violet, horizontal and recurved distally; floral tube 0.2–0.5 cm; sepals ovate, shallow apical notch, narrowed at base, 2–3 cm long, 0.6–1.1 cm wide, obvious median ridge cream-colored with violet spots, a lateral ridge on either side of the median, yellow patch between lateral ridges and extending beyond ridges; petals light violet, rotund, apical notch, 1.6–2.1 cm long, ca. 1.0 cm wide, clawed in lower 1/4; stamens cream, ca. 0.8 cm long, anthers = filaments; style branches petaloid, light violet, ca. 1 cm long, 0.3 cm wide, bi-lobed distally, lobes ca. 0.4 cm long, stigma broad, slightly rounded. Capsule rounded, ca. 1 cm long. Seed light to medium brown, ca. 0.4 cm, with conspicuous white appendage. Flowering: April to May.
Illustration of I. dabashanensis. A Habit B inflorescence C sepal D petal E style branch, anther F fruit G stolon, roots, tubers H root tuber (Source: A–E D. Probst CPC3.5.01.3 (UC); F photograph by Marty Schafer and Jan Sacks; G, H photograph by D. Probst, photographs available from author).
Iris dabashanensis is known from the Daba Mountains in Sichuan and Hubei Provinces and Chongqing Municipality (Fig.
The new species is named for the Daba Mountains in China where it occurs.
Following the criteria and categories of
China. 4 ⚥ Chongqing Municipality, Chengkou County; 29 April 1958; T.L. Dai leg.; 100265; HNWP 34156, PE 01012365, SZ 00043052, SZ 00043057; · 5 ⚥ Chongqing Municipality: Chengkou County; 1 May 1958; T.L. Dai leg.; 100335; CDBI 0169543, IBK 00251078, SZ 00043056, PE 00034001, PE 01012364; · 4 ⚥ Chongqing Municipality: Liangzhong Hewu ji, Chengkou County; 20 April 1958; T.L. Dai leg.; 100150; PE 00034002, SZ 00043055, HNWP 34209, IBK 00251010; · 1 ⚥ Chongqing Municipality: Liang Yizh, Chengkou County; 2 April 1958; T.L. Dai leg.; 100154; CDBI 0169546; · 6 ⚥ Chongqing Municipality: Yizi Liang Hengyan pengwuji, Chengkou County; 24 May 1958; T.L. Dai leg.; 100583; IBK 00081641, CDBI 0169544, CDBI 0169545, HNWP 34583, SZ 00043061, PE 01012366; · 1 ⚥ Chongqing Municipality: Chengkou County; sin. date; Farges leg.; 101; P 02163317; · 4 ⚥ Chongqing Municipality: Chengkou County; 1892; Farges leg.; 1024; P 02163312, P 02163313, P 02163314, P 02163316; · 11 ⚥; Hubei Province: Shennongjia Forest Region; 27 April 2014; Du Wei leg.; 1407; WH 1933.
The date on the specimen T.L. Dai 100154 was 1918 but the collections made at the same time and place had a date of 1958 which is consistent with Dai’s numbering of specimens and other collections.
Morphologically similar to I. henryi, the new species differs in having wider sepals (ca. 7 mm versus 4 mm) and style branch lobes that are shorter (ca. 2–3 mm versus 6 mm).
China. Guizhou Province: about 24 km south of Yanhe on road to Xiushan, 970 m, 28°25.643'N, 108°42.044'E, 24, July 2003 (fl), voucher from cultivated material, D. Probst CPC24.7.03.1 (holotype: UC!; isotypes: PE!, E!).
Small evergreen herbaceous plant with aerial flowering stems shorter than basal leaves. Bracts, cauline leaves, base of basal leaves ± tinged with red. Rhizomes short (< 4 mm), branched, hidden by leaf remains. Stolons present. Roots highly branched distally with small tubers. Basal leaves distichous, linear with acute apex, bright green, slightly glossy on upper surface, dull green on lower surface, leaf edges obscurely membraneous, 12–40 cm long, 0.4–0.6 cm wide, veins slightly thickened; crowded in clumps. Flowering stem ca. 15 cm with 2 (3) cauline leaves on lower half. Inflorescence with two opposite bracts (spathes) subtending 2 (3) flowers, terminal flower opening first with a single bract subtending each subsequent flower; lower bracts ± unequal, 3.5–6 (7) cm long, 0.4–0.5 cm wide; pedicels long (3–4.5 cm) and slender. Flowers cream with light violet, open, ca. 3 cm diameter, radial with petals slightly angled upward, sepals horizontal and recurved distally; floral tube 0.3–0.4 cm; sepals cream adaxially, light yellow abaxially, narrowly obcordate, ± shallow apical notch, narrowed at base, 2.2–2.9 cm long, 0.6–0.9 wide, obvious yellow-orange median ridge, purple spot beginning at ca. midpoint and extending distally beyond ridge with two bright yellow patches flanking ridge distally; petals cream with light violet tint that is more prominent along median, narrowly spathulate, 1.8–2.2 cm long, 0.6–0.7 cm wide, clawed in lower 1/4; stamens cream, ca. 1 cm long, anthers = filaments; style branches medium violet, 1.2–1.5 cm long, 0.3–0.4 cm wide, bi-lobed distally, light violet lobes ca. 0.2–0.3 cm long with several teeth, stigma broad, slightly rounded. Capsule rounded with short apical beak. Seed light to medium brown, ca. 0.4 cm, with conspicuous white appendage. Flowering: April to May.
Iris probstii is currently known from two locations south of Yanhe in Guizhou Province China (Fig.
The new species is named in honor of the U.S. horticulturist, Darrell Probst, in recognition of his work to expand our knowledge of species from series Chinenses in their native habitats.
Following the criteria and categories of
China. Guizhou Province: about 55 km south of Yanhe on road to Xiushan, 825 m, 28°19.651'N, 108°41.390'E, 9, January 2002 (fl), D. Probst CPC9.1.02.2 (photo of living plant, UC).
D. Probst collected a small rhizome segment at the second site that he grew but did not voucher. An image of the plant was obtained for documentation and deposited in UC. A specimen voucher will be made and also deposited at UC when the plant reflowers.
Morphologically these two new species are most similar to I. henryi because they share several characters, including long (> 2.5 cm) slender pedicels, short floral tubes, and narrow leaves (< 0.6 cm). Iris odaesanensis shares the characters of short floral tubes and long pedicels with the two new species and I. henryi but it has leaves that are about 1 cm in width. Molecular data indicates that the two new species are closely related to I. odaesanensis. Unfortunately, because materials of I. henryi were not available for molecular studies it is unknown if all series Chinenses species with short floral tubes and long pedicels are resolved in a clade. These four species can easily be distinguished from each other using several characters. Iris odaesanensis has flowering stems that are almost equal or slightly longer than leaves at flowering while I. dabashanensis, I. henryi, and I. probstii have flowering stems that are substantially shorter than their leaves at flowering. Iris dabashanensis has very narrow (ca. 1–2 mm) leaves while the width of I. henryi and I. probstii leaves are similar at 4–6 mm. Iris dabashanensis also has a median and two lateral ridges while I. henryi, I. odaesanensis, and I. probstii have only a median ridge. Iris probstii has style branches where lobes are 0.2–0.3 cm long which is ca. 1/4 of their total length while lobes in I. dabashanensis and I. henryi are > 0.4 cm and ca. 1/2 of their total length.
Both I. dabashanensis and I. probstii occur in areas that are rocky and considered limestone rich. The border area between Chongqing Municipality and Guizhou Province south of Yanhe, where I. probstii occurs, is considered a karst region with a deep layer of limestone and dolomite and characteristic landforms of caves, sinkholes, outcrops, natural bridges, and gorges. Guizhou Province is one of four provinces that make up the South China Karst, UNESCO World Heritage Site. The Daba Mountains are also rich in limestone and on the northwestern slopes of the Daba Mountains in Shaanxi Province there is a large region of karst. However, the southern slopes of the Daba Mountains above the Sichuan Plateau where I. dabashanensis occurs is not considered a karst region although the soils are calcareous.
An examination of available materials suggests that I. cavaleriei and I. grijsi are similar to each other but morphologically distinct from I. speculatrix. They are also morphologically distinct from the two new species and other series Chinenses species. Previous research utilizing molecular data (
It is surprising that during this study of over 450 specimens representing six Iris species with collections in southern China, only three were collected in Guizhou Province. Guizhou Province is a mountainous rural region that is recognized as having high plant diversity (
1 | Leaves > 1 cm wide | 2 |
– | Leaves < 1 cm wide | 3 |
2 | Floral tube ca. 1 cm long, flowers yellow | I. koreana |
– | Floral tube ca. 0.5 cm long, flowers white | I. odaesanensis |
3 | Floral tube > 2.0 cm long, pedicels < 2 cm long | 4 |
– | Floral tube < 1.0 cm long, pedicels > 2 cm long | 6 |
4 | Floral tube ca. 6 cm long | I. rossii |
– | Floral tube 2–3.5 cm long | 5 |
5 | Flowers pale violet, floral tube 2.5–3.5 cm long | I. proantha |
5a | Flowering stem to bract < 5 cm tall, leaves < 0.4 cm wide | var. proantha |
– | Flowering stem to bract > 7 cm tall, leaves > 0.5 cm wide | var. valida |
– | Flowers yellow, floral tube ca. 2 cm | I. minutoaurea |
6 | Leaves < 3 mm wide, lateral crests flanking median | I. dabashanensis |
– | Leaves > 3 mm wide, median crest only | 7 |
7 | Style branch lobes 2–3 mm long, sepals ca. 7 mm wide | I. probstii |
– | Style branch lobes ca. 6 mm long, sepals ca. 4 mm wide | I. henryi |
I thank Jan Sacks and Marty Schafer for information on seed characteristics, photographs of fruits for both species, and helpful comments on an earlier version of the manuscript, Darrell Probst for photographs of underground structures of I. dabashanensis and information on his collections of these two new species, and X. Zhang for searching for the type locality of I. henryi. I also thank Jaemin Lee who assisted with phylogenetic analyses, Diane Bland who illustrated the new species, reviewers, David Boufford, Manuel Crespo, and Evgeny Mavrodiev, who provided valuable comments, and the associate editor for this paper, Lorenzo Peruzzi. Suggestions by David Boufford were particularly helpful because of his knowledge of the flora and geography of China.
Publication made possible in part by support from the Berkeley Research Impact Initiative (BRII) sponsored by the UC Berkeley Library.
Supplementary file for Dryad
Data type: Nucleotide dataset, phylogenetic tree
Explanation note: This is a draft file for submission to Dryad as supporting materials.