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Research Article
A new species and a replacement name in Cynanchum (Apocynaceae, Asclepiadeae) from China
expand article infoMiao Liao‡§|, Si-Jin Zeng#, Lin-Ya Zeng#, Hai-Jun Yin¤, Mao-Lin Yan¤, Cai-Fei Zhang§|, Guang-Da Tang«‡
‡ South China Agricultural University, Guangzhou, China
§ Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, China
¶ University of Chinese Academy of Sciences, Beijing, China
# South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
¤ Tongbiguan Provincial Nature Reserve, Ruli, China
« Shaoguan University, Shaoguan, China

Corresponding author: Si-Jin Zeng ( kaileqixia@gmail.com )

Academic editor: Petra De Block
© 2024 Miao Liao, Si-Jin Zeng, Lin-Ya Zeng, Hai-Jun Yin, Mao-Lin Yan, Cai-Fei Zhang, Guang-Da Tang.
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: Liao M, Zeng S-J, Zeng L-Y, Yin H-J, Yan M-L, Zhang C-F, Tang G-D (2024) A new species and a replacement name in Cynanchum (Apocynaceae, Asclepiadeae) from China. PhytoKeys 241: 49-63. https://doi.org/10.3897/phytokeys.241.111499
Open Access

Abstract

Cynanchum pingtaoi S.Jin Zeng, G.D.Tang & Miao Liao, sp. nov. (Apocynaceae) from Yunnan Province, China, is described and illustrated based on morphological and molecular evidence. Its deeply cordate to reniform leaves and campanulate, large flowers show that it is a member of former Raphistemma Wall., which has been included in Cynanchum L.. It is different from all former Raphistemma species by the broadly ovate corolla lobes, purple-red corolla and connivent corona tip slightly exceeding the corolla throat. Meanwhile, Cynanchum longhushanense G.D.Tang & Miao Liao, nom. nov. is proposed as replacement name for Raphistemma brevipedunculatum Y.Wan, which was considered a synonym of Cynanchum hooperianum (Blume) Liede & Khanum but is here reinstated as a distinct species because of significant morphological differences.

Key words

Cynanchum hooperianum, Cynanchum longhushanense, Cynanchum pingtaoi, morphology, phylogeny, Raphistemma, taxonomy

Introduction

Cynanchum L. is one of the largest genera of Asclepiadeae (Apocynaceae) and is mainly distributed in Africa and Asia, but it occurs as well in the New World (Khanum et al. 2016; Endress et al. 2018). It is considered a “dustbin genus” due to its complex morphological characteristics, but species generally possess a gynostegial, at least basally fused corona (Liede and Kunze 1993). The extent and classification of Cynanchum are controversial. Markgraf (1972) and Ali and Khatoon (1982) supported Cynanchum and Vincetoxicum Wolf as separate. However, other studies did not support this circumscription (Tsiang and Li 1977; Li et al. 1995). Woodson (1941) and Liede (1997) suggested Cynanchum should include more than twenty allied genera but not Vincetoxicum. Recent studies, based on molecular and morphological evidence, changed the Cynanchum circumscription, including more than ten genera (e.g., Raphistemma Wall.) (Khanum et al. 2016) and segregating Vincetoxicum (Qiu et al. 1989; Liede 1996, 2001; Rapini et al. 2007). A wide concept of the genus with about 250 spp. has been accepted (Khanum et al. 2016; Endress et al. 2018), and the newly circumscribed Cynanchum generally comprises species which possess a corolla 3–10 (–40) mm long, a highly variable gynostegial corona, usually with a ring of fused staminal and interstaminal parts, the staminal parts occasionally with an adaxial appendage, occasionally with additional free staminal lobes connate to ring (Endress et al. 2018).

Cynanchum is a large and complex genus, and the Chinese representatives of Cynanchum have not been completely revised since the “Flora of China” (Li et al. 1995). The number of species of Chinese Cynanchum recorded in databases and literature references differs considerably, e.g., “Flora of China” reports 57 species of Cynanchum in China (Li et al. 1995); Plants of the World Online (POWO, https://powo.science.kew.org/) cites 45 species (including C. heydei Hook.f. distributed in Xizang, China and C. lanhsuense T.Yamaz. which occurs only in Taiwan, China); Catalogue of Life China 2023 Annual Checklist (http://www.sp2000.org.cn/CoLChina) cites 44 species; and Xu et al. (2021) cite 45 species. Of the 57 species of Cynanchum reported by “Flora of China”, 26 species now belong to Vincetoxicum (Liu 2023; POWO 2024) (Suppl. material 1) and Cynanchum includes nine species originally housed in allied genera, notably Adelostemma gracillimum (Wall. ex Wight) Hook.f., Graphistemma pictum (Champ. ex Benth.) Maxim., Holostemma ada-kodien Schult., Metaplexis hemsleyana Oliv., M. japonica (Thunb.) Makino, Raphistemma hooperianum (Blume) Decne., R. pulchellum (Roxb.) Wall., Sichuania alterniloba M.G.Gilbert & P.T.Li. (Khanum et al. 2016), and Sarcostemma acidum (Roxb.) Voigt (Liede and Kunze 2002; Liede and Täuber 2002). Besides, three species were missed by the authors of “Flora of China”, which are C. defilippii Delponte (Delponte 1871), C. kaschgaricum Y.X.Liou (Liou et al. 1992) and C. lanhsuense T.Yamaz. (Yamazaki 1968). Also, recent studies described three new species of Cynanchum from China (Grubov 2000; Shen et al. 2019; Xu et al. 2021). Currently, 46 species of Cynanchum occur in China.

During a field survey in 2020, we collected an unknown species in Ruili, Yunnan. This species has the typical characters of former Raphistemma species with large and reniform leaves, and large and campanulate corollas. Four names were recorded in Raphistemma: R. ciliata Hook.f. was treated as a synonym of Pergularia daemia (Forssk.) Chiov. (Goyder 2006); R. pulchellum was revised to C. pulchellum (Roxb.) Liede & Khanum (Khanum et al. 2016); R. brevipedunculatum Y.Wan was considered a synonym of R. hooperianum, which has been revised to C. hooperianum (Blume) Liede & Khanum (Li et al. 1995; Khanum et al. 2016). After careful examination of the specimens and literature of former Raphistemma, we are unable to match the newly collected material with any recorded species. Therefore, we here describe the newly collected material as a new species of Cynanchum. Meanwhile, we found significant morphological differences between R. brevipedunculatum and R. hooperianum. We therefore propose to reinstate Raphistemma brevipedunculatum at species level in the genus Cynanchum: since the name is already in use within the genus, a replacement name is necessary and proposed here.

Material and methods

Morphological observation

For the new species, field observations were done and a collection made in Ruili City, Yunnan Province (specimen voucher: Si-Jin Zeng & Lin-Ya Zeng SJ4825 (IBSC)). We collected a living sample of R. brevipedunculatum from the type locality (Longhushan Nature Reserve, Longan County, Guangxi Zhuang Autonomous Region (specimen voucher: Miao Liao LM78 (IBSC)). Literature referring to Cynanchum pulchellum, C. hooperianum, and R. brevipedunculatum was consulted, including protologues (Blume 1826; Wan 1983) and other literature (Wallich 1831; Decaisne 1844; Backer and Bakhuizen van den Brink 1965; Li et al. 1995; Khanum et al. 2016). Specimens of C. hooperianum, C. pulchellum, and R. brevipedunculatum at CANT, GXMI, HIB, IBSC (herbaria acronyms follow Thiers 2022) and specimen images from the Chinese Virtual Herbarium (CVH, http://www.cvh.ac.cn), GXSP, National Specimen Information Infrastructure (NSII, http://www.nsii.org.cn), the Global Biodiversity Information Facility (GBIF, https://www.gbif.org/), the JSTOR Global Plants database (https://plants.jstor.org/), P (http://science.mnhn.fr/institution/mnhn/collection/p/item/search/form), and TI (http://umdb.um.u-tokyo.ac.jp/DShokubu) were checked. Morphological data of R. brevipedunculatum is based on living plants, specimens collected in the field and protologues (Wan 1983). Characteristics of C. hooperianum are taken from Decaisne (1844) and Backer and Bakhuizen van den Brink (1965) and those of C. pulchellum from Wallich (1831) and Backer and Bakhuizen van den Brink (1965).

Phylogenetic analysis

DNA extraction, sequencing, assembly, and annotation

We obtained total genomic DNA of the new species and R. brevipedunculatum from fresh leaf material dried in silica gel with the plant genomic DNA kit (DP305, Tiangen, Beijing, China). The samples were sent to Novogene (Tianjin, China) for library preparation (350 bp) for genome skimming sequencing. We used an Illumina HiSeq 2000 to conduct a paired-end sequencing (150 bp), generating 10 Gb raw data for each sample. After quality control of the raw data using fastp 0.19.7 (Chen et al. 2018: parameter settings fastp -g -q 5 -u 50 -n 15 -l 150), we extracted 3 Gb paired reads for plastid and nuclear ribosome assembly using GetOrganelle v.1.7 with the parameters “-t 30 -R 15 -k 21,45,105,115,127 -F embplant_pt” and “-t 30 -R 7 -k 35,85,115 -F embplant_nr” respectively (Jin et al. 2020).

A plastid genome of Apocynum venetum L., a continuous sequence (18S-ITS1-5.8S-ITS2-26S) of the ribosome genome of Asclepias albicans S.Watson, and the nrETS of Calciphila galgalensis (Liede) Liede & Meve and Cynanchum adalinae (K.Schum.) K.Schum. (GenBank accession numbers: MT313688, JN665082, LN896997, and LN897003) were used as respective references. We employed Geneious Prime 2019 (https://www.geneious.com) to annotate and extract three plastid DNA markers (one spacer of trnL-F and two introns of rps16 and trnL) and two nuclear DNA regions (nrITS: internal transcribed spacer; nrETS: external transcribed spacer). New sequences of the five loci were uploaded to GenBank with accession numbers OP810602–OP810613 and OP853101–OP853103 (https://www.ncbi.nlm.nih.gov/).

Taxa sampling, alignment, and phylogenetic analysis

Sequences of the new species and R. brevipedunculatum were added to a reduced matrix of Khanum et al. (2016) with combined data of five loci (nrETS, nrITS, rps16, trnL, and trnL-F) for phylogenetic analysis (Suppl. material 2). We used 57 samples for molecular analysis, including 50 samples (49 species) of Cynanchum, covering all nine clades in Khanum et al. (2016). Of the former Raphistemma species, we included C. pulchellum and C. hooperianum (in fact a specimen belonging to R. brevipedunculatum). Seven samples were taken as outgroups: Pentatropis madagascariensis Decne., P. nivalis (J.F.Gmel.) D.V.Field & J.R.I.Wood, and P. sp. which belong to subtribe Tylophorinae, and Calciphila galgalensis (including two samples), Calciphila gillettii Liede & Meve and Calotropis procera (Aiton) W.T.Aiton which belong to subtribe Asclepiadinae.

We aligned sequences of the three plastid markers and two nuclear regions separately using the MUSCLE optional in the software MEGA v.7.0.26 (Kumar et al. 2016) and concatenated the data using the Concatenate Sequences or Alignments optional in Geneious Prime 2019 (https://www.geneious.com). The incomplete sequences were filled with missing data.

We used RAxML-HPC2 8.2.12 on XSEDE (Stamatakis 2014) through the CIPRES portal (Miller et al. 2010) to perform Maximum likelihood (ML) analysis by using the GTRCAT model and 1 000 bootstraps. Finally, we viewed and edited the tree in Figtree 1.4.2 (Rambaut 2012).

Results

Morphological comparison

The new species resembles Cynanchum hooperianum, C. pulchellum, and Raphistemma brevipedunculatum, but differs from them by the broadly ovate corolla lobes, purple-red corolla, and connivent corona apex slightly exceeding the corolla throat (Table 1).

Table 1.
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Morphological comparison of Cynanchum pingtaoi and closely related species.

Characters Cynanchum pingtaoi Cynanchum hooperianum Cynanchum pulchellum Cynanchum longhushanense (Raphistemma brevipedunculatum)
Calyx length ca. 6 mm 3–4 mm 3–4 mm 5–6 mm
Corolla-tube length 12–14 mm 8–9 mm 12–18 mm 12–16 mm
Corolla lobe shape Broadly ovate (Fig. 4h) Ovate Ovate-oblong Oblong (Fig. 2i)
Corolla color Outer surface greenish-white, inner surface purple-red (Fig. 4h) Outer surface light green, inner surface white, with purple spots near the top of corolla lobe Outer surface slightly greenish, inner surface white Outer surface greenish-white, inner surface white (Fig. 2i)
Corona-scales apex Connivent, corona apex slightly exceeding corolla throat (Fig. 3e) Separate, reaching the middle of the corolla-segments or further Barely connivent, slightly exceeding corolla throat Connivent, not exceeding corolla throat (Fig. 2h)
Follicles Fusiform, with three ribs Not observed Oblong, without ribs Fusiform, with three ribs

Raphistemma brevipedunculatum is significantly different from Cynanchum hooperianum by the longer calyx lobes (5–6 mm vs. 3–4 mm), the longer corolla-tubes (12–16 mm vs. 8–9 mm), the oblong corolla lobes (vs. ovate), and the corona lobes with connivent corona-scales apex, not exceeding the throat of the corolla (vs. corona-scales apex separate, reaching the middle of the corolla-segments or further). Raphistemma brevipedunculatum flowers in June–July (Wan 1983), but Cynanchum hooperianum flowers almost all year (Blume 1826).

Molecular phylogenetics

The combined phylogenetic analysis shows that the new species forms a monophyletic clade (BS = 100%, Fig. 1, Suppl. material 3) with two former Raphistemma species. The two former Raphistemma species (C. pulchellum and R. brevipedunculatum) are sister species (BS = 100%, Fig. 1, Suppl. material 3).

Figure 1. 

Simplified maximum likelihood tree of Cynanchum based on two nuclear regions (nrETS and nrITS) and three plastid markers (rps16 and trnL introns, and trnL-F spacer). Bootstrap support values are given for each node. See Suppl. material 3 for maximum likelihood tree. Clade designations follow those of Khanum et al. (2016) and names in parentheses are the corresponding names that were used in Khanum et al. (2016).

Taxonomic treatments

Cynanchum longhushanense G.D.Tang & Miao Liao, nom. nov., non Cynanchum brevipedunculatum J.Y.Shen et al. (2019: 217).

urn:lsid:ipni.org:names:77339615-1
Fig. 2

≡ Raphistemma brevipedunculatum Y.Wan, in Guihaia 3(3): 197 (1983).

Type

China. Guangxi: Longan County, Longhushan Nature Reserve, open woods, 2 Jul. 1981, D.H. Tan 81329 (holotype: GXSP[GXSP0000038!]; isotype: CANT[CANT00002128!]).

Chinese name

Guangxi Dahuateng (广西大花藤).

Notes

Raphistemma brevipedunculatum was considered a synonym of R. hooperianum (Li et al. 1995), which was transferred to Cynanchum as C. hooperianum (Khanum et al. 2016). Although C. hooperianum is not included in our molecular study, morphological differences between specimens of C. hooperianum and R. brevipedunculatum are significant. We therefore reinstate R. brevipedunculatum as a distinct species of Cynanchum. We renamed Raphistemma brevipedunculatum as Cynanchum longhushanense because the specific epithet ‘brevipedunculatum’ is occupied in Cynanchum (C. brevipedunculatum J.Y.Shen). C. longhushanense differs from C. hooperianum by the longer calyx lobes (5–6 mm vs. 3–4 mm), the longer corolla-tubes (12–16 mm vs. 8–9 mm), the oblong corolla lobes (vs. ovate), and the corona lobes with connivent corona-scales apex, not exceeding the throat of the corolla (vs. corona-scales apex separate, reaching the middle of the corolla-segments or further). It should be noticed that in the protologue of Cynanchum longhushanense (≡ R. brevipedunculatum) (Wan 1983), the number of glands at the base of the calyx was described as five, but we observed 10–15 glands per calyx in our Guangxi collection (Fig. 2j). More specimens are expected to be collected to determine the morphological variation.

Figure 2. 

Cynanchum longhushanense G.D.Tang & Miao Liao a flowering branch b cross-section of hollow stem c node with small glands d petiole with glands at the top e inflorescence f bracteoles at the base of the pedicel g flower bud (above: top view; below: side view) h flower (1) top view, (2) lateral view, showing the connivent corona-scales apex, not exceeding the throat of the corolla, (3) side view, showing corolla lobes overlapping to the right and corolla tube i opened corolla, adaxial (above) and abaxial (below) view j ovary with calyx (above: top view, showing glands at the base of the calyx, below: side view of ovary, calyx and pedicel) k ovary l calyx lobes m gynostegium with corona lobes n gynostegium o corona lobes p pollinarium. All photos based on Miao Liao LM78.

Other specimens examined

China. Guangxi: Longan County, Pingshan Village, 10 Oct. 1977, Longan Investigation Team 2-040 (GXMI[GXMI031735!]); Longan County, Longhushan Nature Reserve, 14 Nov. 1982, Y. Wan & Rui-Ju Liu 82430 (paratype: GXSP[GXSP0000039!]); Longan County, Longhushan Nature Reserve, 25 Jun. 2021, Miao Liao LM78 (IBSC).

Cynanchum pingtaoi S.Jin Zeng, G.D.Tang & Miao Liao, sp. nov.

urn:lsid:ipni.org:names:77339616-1
Figs 3, 4

Type

China. Yunnan: Dehong Dai and Jingpo Autonomous Prefecture, Ruili City, Nongdao Town, Tongbiguan Provincial Nature Reserve, 23°57'N, 97°32'E, elev. 839 m, 24 Aug. 2020, Si-Jin Zeng & Lin-Ya Zeng SJ4825 (holotype, IBSC[IBSC1009908!]; isotypes, IBSC [IBSC1009907!], [IBSC1009909!], [IBSC1009910!]).

Diagnosis

Cynanchum pingtaoi resembles C. longhushanense, differing by its broadly ovate corolla lobes (vs. oblong), the purple-red inner surface of the corolla (vs. white), and the corona-scales apex connivent, slightly exceeding the corolla throat (vs. corona-scales apex connivent, not exceeding the throat of the corolla).

Figure 3. 

Cynanchum pingtaoi S.Jin Zeng, G.D.Tang & Miao Liao a follicle and leaves b inflorescence c glands at the base of leaf d top view of flower e side view of flower with two corolla lobes removed f calyx g corolla lobes (each lobe attached to part of the corolla tube), outer surface on the right, inner surface on the left (four drawn) h corolla separation, showing gynostegium with corona lobes i pollinarium j seed. Illustration based on Si-Jin Zeng & Lin-Ya Zeng SJ4825 (IBSC), and drawn by Ding-Han Cui.

Description

Twining liana. White latex in stems and leaves. Branchlets fistulous, smooth, glabrous, slightly woody. Leaves opposite; petiole 6–14 cm long, smooth, sparsely white puberulent, later glabrescent, with small yellowish-brown glands at the apex, nodes with small glands; leaf blade deeply cordate to reniform, 7–15 × 4–13 cm, membranous, base cordate, apex acuminate, margin entire, adaxial surface dark green, glabrous, abaxial surface light green, sparsely white puberulent on veins, gradually glabrescent later; basal veins five or seven, palmate, secondary veins three to five pairs, pinnate, tertiary veins reticulate, smooth adaxially, raised abaxially. Inflorescences extra-axillary, subumbellate to subracemic, 5–11 flowers; peduncle 10–12 cm long, smooth; pedicel 3.0–5.5 cm long, smooth, sparsely white puberulent near the base, base with bracteoles triangular, ca. 0.1 × 0.1 cm. Calyx yellowish green, basally fused, lobes elliptic, ca. 0.6 × 0.5 cm, inside the base with small glands, apices obtuse, margins ciliate. Corolla campanulate, glabrous, external surface greenish white, inner surface purple-red, 3.3–3.5 cm in diam; lobes slightly longer than tube, tube 1.2–1.4 cm, lobes broadly ovate, 1.3–1.8 × 1–1.2 cm, apices reflexed, overlapping to the right. Corona lobes linear-subulate, white, separate, ca. 1.1 cm long, inserted at base of gynostegium, longer than gynostegium, corona-scales apex connivent, slightly exceeding corolla throat. Anthers ca. 0.7 × 0.4 cm, apices with inwardly incurved wings. Stigma broadly rounded, slightly depressed, white. Pollinia 2 per pollinarium, ellipsoid, yellow, pendulous, ca. 0.13 × 0.08 cm, caudicle ca. 0.05 cm long, retinaculum ca. 0.1 cm long. Follicles solitary, fusiform, ca. 14.5 cm long, ca. 5 cm diam., glabrous, with a thick fibrous pericarp, triangulate, apex curved outwards; seeds ovoid, 0.8 cm × 0.6 cm, tipped with a white silky coma; coma 3.8–4.2 cm long.

Figure 4. 

Cynanchum pingtaoi S.Jin Zeng, G.D.Tang & Miao Liao a habitat b inflorescence and leaf c inflorescence d flower buds e top view of flower f bracteoles at base of pedicel g side view of flower h corolla and corona separation, showing gynostegium, corona and corolla lobes (outer surface: upper right hand corner; inner surface: to the left of the outer surface) i pollinarium from dry specimen j young seeds k longitudinally opened half follicle showing seed arrangement l follicle, different views to show the three ribs m transverse section through follicle n follicle and leaves. All photos based on Si-Jin Zeng & Lin-Ya Zeng SJ4825 (IBSC).

Etymology

The specific epithet pingtaoi honors the eminent botanist Ping-Tao Li (李秉滔), who is an expert in the Apocynaceae.

Chinese name

Bingtao Dahuateng (秉滔大花藤).

Distribution

Endemic to China. Only one population was found at the border of China-Myanmar in Ruili, Yunnan Province, China. Fig. 5.

Figure 5. 

Distribution map of Cynanchum pingtaoi and the three Cynanchum species formerly were considered to belong to Raphistemma based on specimens cited in Suppl. material 4. The base map [No. GS(2016)1666] was downloaded from http://bzdt.ch.mnr.gov.cn/.

Habitat and phenology

This species occurs near open woods at an elevation of about 850 m. Flowering was observed from September to October, fruiting from November to December.

Provisional IUCN assessment

The species is currently known only from the type locality, where only a few individuals were seen. Suitable habitat exists in the proximity of the type locality. Nevertheless, as there is no reliable information on the population size or distribution of this species, we propose to treat it as Data Deficient (IUCN 2019).

Notes

The large and reniform leaves, campanulate corolla, and lanceolate corona indicate that this species is morphologically close to the former Raphistemma species, which have been included in Cynanchum (Khanum et al. 2016). The molecular phylogenetic analyses also showed that Cynanchum pingtaoi is sister to C. pulchellum + C. longhushanense (Fig. 1; Suppl. material 3). We do not currently possess molecular data of C. hooperianum, but the new species can be distinguished from this species by the purple-red inner surface of the corolla (vs. white inner surface of the corolla with purple spots near the top of the corolla lobes), the connivent corona-scales apex, slightly exceeding the corolla throat (vs. corona-scales apex separate, and reaching the middle of the corolla-segments or somewhat further), the longer calyx-segments (6 mm vs. 3–4 mm), and the longer corolla-tubes (12–14 mm vs. 8–9 mm).

Acknowledgements

This work was supported by the Science and Technology Program from the Forestry Administration of Guangdong Province (2023KJCX001). We are thankful to Prof. Nian-He Xia (South China National Botanical Garden) and Dr. Gang Yao (South China Agricultural University) for their helpful comments and constructive suggestions, and to Guangxi Longhushan Provincial Nature Reserve for supporting our fieldwork, and to the Herbarium of the Guangxi Health Science College (GXSP) for providing the digital specimen images of Cynanchum longhushanense. This paper has been carefully supervised and reviewed by Dr. Guang-Da Tang who was the supervisor of the first author, Miao Liao, but unfortunately passed away on 15 January 2024. We would like to express our deepest remembrance of him here.

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

No ethical statement was reported.

Funding

This work was supported by the Science and Technology Program from the Forestry Administration of Guangdong Province (2023KJCX001).

Author contributions

Miao Liao: Data curation (Lead); Formal analysis (Lead); Investigation (Supporting); Methodology (Lead); Software (Lead); Validation (Equal); Visualization (Lead); Writing – original draft (Lead); Writing – review & editing (Equal). Si-Jin Zeng: Conceptualization (Supporting); Formal analysis (Equal); Investigation (Lead); Writing – review & editing (Supporting). Lin-Ya Zeng: Investigation (Supporting); Resources (Supporting). Hai-Jun Yin: Investigation (Equal). Mao-Lin Yan: Investigation (Equal). Cai-Fei Zhang: Data curation (Equal); Validation (Equal); Writing – review & editing (Supporting). Guang-Da Tang: Conceptualization (Lead); Data curation (Equal); Formal analysis (Supporting); Funding acquisition (Lead); Methodology (Supporting); Project administration (Lead); Resources (Supporting); Supervision (Lead); Validation (Lead); Writing – review & editing (Lead).

Author ORCIDs

Miao Liao https://orcid.org/0000-0003-2545-9419

Si-Jin Zeng https://orcid.org/0000-0002-3256-0286

Lin-Ya Zeng https://orcid.org/0000-0002-4788-1867

Hai-Jun Yin https://orcid.org/0009-0004-9804-1958

Mao-Lin Yan https://orcid.org/0009-0003-5188-6796

Cai-Fei Zhang https://orcid.org/0000-0002-2818-5751

Guang-Da Tang https://orcid.org/0000-0001-5623-3928

Data availability

The newly obtained sequences of Cynanchum pingtaoi and C. longhushanense have been submitted to the NCBI website. The DNA sequence data supporting the findings of this study are available in Suppl. material 2.

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Supplementary materials

Supplementary material 1 

List of species names changes within Cynanchum in Flora of China

Miao Liao, Si-Jin Zeng, Lin-Ya Zeng, Hai-Jun Yin, Mao-Lin Yan, Cai-Fei Zhang, Guang-Da Tang

Data type: xlsx

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (12.82 kb)
Supplementary material 2 

List of ingroup and outgroup taxa used in the phylogenetic analyses

Miao Liao, Si-Jin Zeng, Lin-Ya Zeng, Hai-Jun Yin, Mao-Lin Yan, Cai-Fei Zhang, Guang-Da Tang

Data type: xlsx

Explanation note: List of ingroup and outgroup taxa used in the phylogenetic analyses with voucher information (geographic origin, collection, herbarium) and Genbank accession numbers. “*” indicates new sequences; “–” indicates missing sequences; bold GenBank accession numbers indicate connected sequences for trnL intron and trnL-F intergenic spacer.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (57.75 kb)
Supplementary material 3 

Maximum likelihood tree of Cynanchum

Miao Liao, Si-Jin Zeng, Lin-Ya Zeng, Hai-Jun Yin, Mao-Lin Yan, Cai-Fei Zhang, Guang-Da Tang

Data type: pdf

Explanation note: Maximum likelihood tree of Cynanchum based on two nuclear regions (nrETS and nrITS) and three plastid markers (rps16 and trnL introns, and trnL-F spacer). Bootstrap support values are given for each node.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (26.01 kb)
Supplementary material 4 

Specimens of Cynanchum hooperianum, C. longhushanense, C. pingtaoi, and C. pulchellum used for the distribution map

Miao Liao, Si-Jin Zeng, Lin-Ya Zeng, Hai-Jun Yin, Mao-Lin Yan, Cai-Fei Zhang, Guang-Da Tang

Data type: docx

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (16.50 kb)
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