Research Article |
Corresponding author: Tao Deng ( dengtao@mail.kib.ac.cn ) Academic editor: Karol Marhold
© 2021 Xin-jian Zhang, Jun-Tong Chen, Ihsan A. Al-Shehbaz, Qun Liu, Li-Juan Li, Peng-Ju Liu, Xian-Han Huang, Tao Deng.
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:
Zhang X-j, Chen J-T, Al-Shehbaz IA, Liu Q, Li L-J, Liu P-J, Huang X-H, Deng T (2021) Smelowskia sunhangii (Brassicaceae), a new species from China, with a re-evaluation of the S. tibetica complex. PhytoKeys 178: 179-191. https://doi.org/10.3897/phytokeys.178.62922
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Smelowskia sunhangii, from Qinghai and Tibet (China), is described and illustrated. Morphological and molecular data indicate that S. sunhangii is closely related to Smelowskia tibetica, from which it is easily distinguished by the densely hirsute (vs. glabrous or sparsely pubescent), elliptic to ovate-lanceolate (vs. suborbicular, oblong, or lanceolate) fruits with undulate (vs. straight) margins. A re-evaluation of the widely distributed S. tibetica and related taxa is also provided.
Brassicaceae, China, Cruciferae, new species, phylogeny, taxonomy
The genus Smelowskia C.A.Mey. (Brassicaceae; Cruciferae) comprises 25 species distributed mainly in central and northeastern Asia, with fewer species in North America (
Nine species of Smelowskia are native to China (
During a recent field survey, we collected an unidentified specimen of Smelowskia in Qinghai province, China (Fig.
Morphological data were recorded from field collections and herbarium specimens covering the full spectrum of geographical, plant type, and habitat variation in the S. tibetica complex. The voucher specimens of our collections were deposited in the herbarium of Kunming Institute of Botany (
Taxon | Voucher | GenBank accession number |
---|---|---|
Smelowskia tibetica (1) (as Hedinia rotundata) |
Yang Jingsheng 402 ( |
MZ089467 |
S. tibetica (2) (as Hedinia lata) |
HuangXH018-9 ( |
MZ089476 |
S. tibetica (4) (as H. lata) |
HuangXH015-20 ( |
MZ089475 |
S. tibetica (5) (as H. lata) |
Deng7359 ( |
MZ089474 |
S. tibetica (6) (as H. tibetica) |
ZDG23-7 ( |
MZ089468 |
S. tibetica (7) (as H. tibetica) |
Deng7261 ( |
MZ089473 |
S. sunhangii (1) |
Deng7262 ( |
MZ089472 |
S. sunhangii (3) |
DengT128-9 ( |
MZ089471 |
S. sunhangii (4) |
HuangXH025-13 ( |
MZ089470 |
S. sunhangii (5) |
DengT105-23 ( |
MZ089469 |
Shehbazia tibetica |
HuangXH028-4 ( |
MZ089466 |
Sequences downloaded from NCBI | ||
Smelowskia sunhangii (2) (as S. tibetica) |
Zh641 ( |
KX244397 |
S. tibetica (3) (as H. lata) |
LJQ-QLS-2008-0115 ( |
JF941772 |
S. czukotica | TC03_60 | EU489520 |
S. altaica | TC03_61 | EU489519 |
S. bartholomewii | Ho et al. 3000 (MO) | AY230609 |
S. sophiifolia | Geonova 148 (LE) | AY230608 |
S. calycina | Velychnin N495 (LE) | AY230604 |
S. borealis | Murray 8582 (DAO) | AY230571 |
S. jacutica | Elias & Murray 11462 (ALA) | AY230646 |
S. johnsonii | Johnson, Viereck, & Melchior 688 (ALA) | AY230631 |
S. ovalis | CCDB-23367-G06 | MG234816 |
S. sisymbrioides | Egorova 2349 (LE) | AY230612 |
S. annua | Anonymous 870473 (HNWP) | AY230610 |
Descurainia pinnata | – | AF183122 |
Shehbazia tibetica (as Dontostemon tibeticus) | GH:33576 | LN713849 |
We sampled 12 collections representing the Smelowskia tibetica complex, including the presumed new species. Leaf materials were collected from field works and dried herbarium specimens. Descurainia pinnata from tribe Descurainieae (sister to tribe Smelowskieae) and Shehbazia tibetica from tribe Chorisporeae were selected as outgroups based on previous molecular phylogenetic relationships (
Total genomic DNA extracted from leaf materials using DP305 Plant Genomic DNA kits (Tiangen, Beijing, China) following the manufacturer’s protocol. The entire ITS region (including internal transcribed spacers ITS1 and ITS2 of nuclear ribosomal DNA and the 5.8S rRNA gene) were amplified using the primers ITS1-18S described in
Phylogenetic reconstruction was performed using Bayesian inference (BI) and maximum likelihood (ML). The phylogenetic tree based on Bayesian inference was generated using MrBayes version 3.2.6 (
Morphological studies of strictly Chinese material revealed a wide variation in fruit indumentum and shape and leaf divisions in the Smelowskia tibetica complex, and such differences lead
Comparison of selected distinguishing features of Smelowskia sunhangii and related taxa.
Taxon | Cauline leaf shape | Fruit shape | Indumentum in silicle | Distribution |
---|---|---|---|---|
Smelowskia tibetica | 1- or 2-pinnatifid | oblong | Glabrous | Qinghai, Tibet, Xinjiang |
S. tibetica (as Hedinia lata) | 2-pinnatifid | oblong | Glabrous | Qinghai, Tibet, Xinjiang |
S. tibetica (as H. taxkargannica) | 1-or 2-pinnatifid | lanceolate | Glabrous | Xinjiang |
S. tibetica (as H. rotundata) | 1-pinnatifid | suborbicular | sparsely pubescent | Xinjiang |
S. sunhangii | 1-pinnatifid | elliptic to ovate-lanceolate | densely hirsute | Qinghai, Tibet |
These densely hirsute plants with densely hirsute, elliptic to ovate-lanceolate fruits undulate along the margin, do not match any of the other 25 species we carefully studied throughout the range of Smelowskia. Therefore, these Qinghai plants are described as the new species S. sunhangii and recognized hereafter as such.
A total of 15 taxa were included in this analysis (Fig.
All of the seven accessions of the Smelowskia tibetica complex formed a monophyletic clade, sister to S. sunhangii with a strong support (PP = 1, ML = 95.7). In addition, the clade of Smelowskia tibetica complex formed a polytomy of three subclades, of which two belong to Smelowskia tibetica and the third is a polytomy of samples identifiable as members of the Hedinia lata and H. rotundata as characterized morphologically above.
Our molecular and morphological analyses indicate that Smelowskia tibetica sensu lato contains two, easily distinguished species, of which one is the new S. sunhangii and the other is S. tibetica including the taxa described by
First and foremost, as discussed above in the section of “Morphology and taxonomy” of the results, the variation in leaf and fruit morphology in the entire Smelowskia tibetica complex was critically studied by one of us (Al-Shehbaz) in plants from the entire range of this complex in Bhutan, India, China, Nepal, and Tajikistan both in herbaria worldwide and in the field in Xinjiang (China), Nepal, and Tajikistan. The conclusion of such observations was the acceptance of a single polymorphic species in the Himalayan region (
Then similar variation in fruit and leaf morphology of the Smelowskia tibetica complex, especially that of the Hedinia taxa discussed above, was observed sporadically elsewhere in the species range and, therefore, the alleged distinction of Hedinia taxa has no merit.
Additionally, although our molecular data show a slight differentiation in the Hedinia taxa (Fig.
Finally, our morphological studies strongly support the novelty of Smelowskia sunhangii because its fruit morphology in unique in the genus and has not yet been observed in Asian and North American taxa. Furthermore, our molecular data also strongly support the above recognition of the novelty and its sister relationship to S. tibetica including the Hedinia taxa of
China. Qinghai. Yushu Tibetan Autonomous Prefecture, Yushu City, Longbao Town, 33°30'13.54"N, 96°24'38.79"E, 4,602 m, 26 July 2019, J.T. Chen, X. Zhang & T.H. Kuang HuangXH025-13 (holotype: KUN1498313!; isotype: KUN1498314!).
Smelowskia sunhangii is easily distinguished from its closest relative S. tibetica by having densely hirsute (vs. glabrous or sparsely pubescent), elliptic to ovate-lanceolate (vs. oblong, suborbicular, or lanceolate) fruits undulate (vs. straight) along margin.
Herbs 5–15 cm tall, covered with simple trichomes, canescent. Stems procumbent or ascending, densely white hirsute. Basal leaves densely hirsute; petiole 0.5–1.5 cm long, often ciliate basally; leaf blade ovate or narrowly oblong in outline, 1-pinnatifid, 1–4 × 1–2.5 cm; cauline leaves similar to basal, reduced in size upwards. Racemes bracteate throughout, distal bracts subsessile. Sepals oblong, 1–2 × 0.5–0.8 mm, hirsute. Petals obovate, 2–3.2 × 0.9–1.4 mm, claw ca. 1.5 mm long. Fruit elliptic to ovate-lanceolate, densely white hirsute, 5–10 × 3–5 mm, undulate along margin, appressed to rachis. Seeds light to dark brown, oblong, 0.9–1.2 × 0.4–0.6 mm. Fl. Jul–Sep, fr. Aug–Oct.
Smelowskia sunhangii is named after Prof. Sun Hang (1963–), director of the Kunming Institute of Botany (China) who conducted extensive research on plant taxonomy, biogeography, and evolutionary biology and made outstanding contributions towards understanding the plant diversity of China. Vernacular name: The Chinese name is given as “毛果藏荠” (máo guǒ zàng jì), referring to the densely hirsute fruit of the new species.
China (Qinghai, Tibet [Xizang], Fig.
China. Tibet: Lhasa, Damxung County, Gangla Mountain, 30°41'6.77"N, 91°6'16.88"E, 4,802 m, 27 July 2018, D.G. Zhang DengT051-14 (
Basionym: Hutchinsia tibetica Thomson, Hooker’s Icon. Pl. 9: t. 900. 1852. TYPE: WESTERN TIBET. Lanak Pass, 18–19,000 ft [ca. 5,480–5,790 m], Thomas Thomson s.n. (holotype: K!).
Synonyms: Hedinia tibetica (Thomson) Ostenf. in Hedin, S. Tibet 6: fig. 2. 1922.
Hedinia lata Xue L.He & C.H.An, Acta Phytotax. Sin. 34(2): 205. 1996. TYPE: TIBET. Ando, alt. 4,750 m, on stony mountain slopes, 14 August 1963, J.X. Yang 2220 (holotype: WUK, n.v.).
Hedinia rotundata C.H.An, Acta Bot. Boreali-Occid. Sinica 10: 325. 1990. TYPE: XINJIANG. The west of Altum Mountains, Qimantag, 2,700 m, 25 July 1984, Zhang Li-Yun 84-A-411 (holotype: XJA!)
Hedinia taxkargannica G.L.Zhou & C.H.An, Acta Bot. Boreal.-Occid. Sin. 10: 323. 1990. TYPE: XINJIANG. Tajik Autonomous County of Taxkargan Vaka, in alpina desert steppe zone, July 1986, An Zheng-xi N. 268 (holotype: XJA!)
Detailed descriptions of the species are found in the Flora of China (
China (Gansu, Qinghai, Sichuan, Tibet, Xinjiang, Fig.
China. Tibet: Baingoin County, 15 August 1988, S.G. Wu, H. Ohba, Y.H. Wu & Y. Fei No. 4095 (
We deeply thank Mr. Dai-Gui Zhang for taking part in the field collections. We are also grateful to Ms. Juan Qiu, of Xinjiang Agricultural University, for providing the type specimen of Hedinia taxkargannica. This study was supported by grants from the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (2019QZKK0502), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20050203), the Key Projects of the Joint Fund of the National Natural Science Foundation of China (U1802232), the Youth Innovation Promotion Association of Chinese Academy of Sciences (2019382), the Young Academic and Technical Leader Raising Foundation of Yunnan Province (2019HB039), the Chinese Academy of Sciences “Light of West China” Program, and the Biodiversity Survey, Monitoring and Assessment (2019HB2096001006).