Soroseris

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Description

Herbs, perennial, rosulate, often acaulescent, sometimes from a stout vertical subterranean rosette shoot with scalelike leaves (cataphylls) below leaf rosette or caulescent with a thick hollow stem. Leaves rosulate or along stem. Rosette shoot inflated at apex to a convex, hollow receptacle or rarely elongated to a hollow cylindric axis, carrying usually numerous, densely crowded capitula. Capitula with 4(or 5) or 15–30 florets; peduncle mostly shorter to rarely longer than involucre. Involucre narrowly cylindric or rarely campanulate. Phyllaries in few series; outer phyllaries mostly 2, linear, similar to uppermost leaves; inner phyllaries 4–15, ± lanceolate, subequal in length, connate or distinct in basal part, herbaceous at maturity. Receptacle naked. Florets yellow, sometimes basally blackish, more rarely white. Achene subcylindric, subfusiform, obcolumnar, or narrowly obconical, subcompressed, with 5 mostly rather slender and sometimes weak main ribs and 1–3(or 4) secondary often ± subequal ribs in between but otherwise smooth, inconspicuously or rarely apically conspicuously acutely papillate, apex ± truncate or rarely shortly beaked. Pappus whitish to strawcolored, often apically grayish, bristles stiff, coarse, scabrid, and usually ± caducous.

from: Shih C. & Kilian N. in Wu Z. Y. & al. (ed.), Flora of China 20–21: 342–343. 2011, Beijing & St Louis.

Distribution

Asia-Temperate: Afghanistan (Afghanistannative); China North-Central (Gansunative, Shaanxinative); China South-Central (Sichuannative, Yunnannative); Qinghai (Qinghainative); Tibet (Tibetnative); Xinjiang (Xinjiangnative) Asia-Tropical: Assam (Meghalayanative); East Himalaya (Bhutannative, Sikkimnative); India (Punjabnative, Uttar Pradeshnative); Nepal (Nepalnative); Pakistan (Pakistannative); West Himalaya (Himachal Pradeshnative, Jammu-Kashmirnative, Uttaranchalnative)

Systematics

Soroseris, established and monographed by Stebbins (1940), is a genus of about seven species, distributed in the Himalayas (Pakistan, Kashmir, India, Nepal, Bhutan) and W China (Gansu, Qinghai, Shaanxi, Sichuan, Sichuan, Xinjiang, Xizang, Yunnan) chiefly in alpine meadows. Its species are all perennial, rosulate and often acaulescent herbs and its capitula are congested in hemispherical or rarely cylindrical synflorescences.

Following Shih & Kilian (in Shih & al. 2011), Soroseris is here treated in a wider sense, also including the two monotypic genera Stebbinsia (accommodating S. umbrella) and Tibetoseris (accommodating T. depressa), see Synonymy. With respect to Stebbinsia, Shih & Kilian (in Shih & al. 2011) refer to the cytological and molecular work by Zhang & al. (2007, 2011), which confirmed that Soroseris and Stebbinsia are congeners. With respect to Tibetoseris, Shih & Kilian (in Shih & al. 2011) refer to the molecular phylogenetic analysis of subtribe Crepidinae by J. W. Zhang & al. (in prep.), which revealed that Youngia depressa, recently separated for convincing morphological reasons from Youngia in the new genus Tibetoseris (Sennikov & Illarionova 2008), which subsequently was recircumscribed similarly convincingly to become a monotypic genus for Y. depressa by Maity & Maiti (2010), actually is also nested in the clade of Soroseris. S. depressa, in fact, well agrees morphologically: it strongly resembles S. umbrella in leaf shape and habit, while in the number of phyllaries it is intermediate between S. umbrella and the remainder of Soroseris.

It has been shown by Zhang & al. (2011) that speciation in Soroseris is rather recent, the relationship between its species being not resolved in their molecular analyses. Also morphologically, distinction between the species is not always easy and more studies are needed.


References


Maity D. & Maiti G. G. 2010: Taxonomic delimitation of the genus Tibetoseris Sennikov and the new genus Pseudoyoungia of the Compositae-Cichorieae from Eastern Himalaya. – Compositae Newslett. 48: 22–42.

Sennikov A. N. & Illarionova I. D. 2008 ["2007"]: Generic delimitation of the subtribe Ixeridinae newly segregated from Crepidiinae (Asteraceae-Lactuceae). – Komarovia 5: 57–115

Shih C., Ge X. J.; Kilian N., Kirschner J., Štěpánek J., Sukhorukov A. P., Mavrodiev E. V. & Gottschlich G. 2011: Cichorieae. – Pp. 195–353 in: Wu Z. Y., Raven P. H. & Hong D. Y. (ed.), Flora of China 20–21. Asteraceae. – Beijing: Science Press & St Louis: Missouri Botanical Garden.

Stebbins G. L. 1940: Studies in Cichorieae: Dubyaea and Soroseris. Endemics of the Sino-Himalayan region. – Mem. Torrey Bot. Club 19(3): 1–76.

Zhang J.-W., Sun H. & Nie E.-L. 2007: Karyological studies on the Sino-Himalayan endemic Soroseris and two related genera of tribe Lactuceae (Asteraceae). – Bot. J. Linn. Soc. 154: 79–87.

Zhang J. W., Nie Z. N., Wen J. & Sun H. 2011: Molecular phylogeny and biogeography of three closely related genera, Soroseris, Stebbinsia, and Syncalathium (Asteraceae, Cichorieae), endemic to the Tibetan Plateau, SW China. – Taxon 60: 15–26.

Common names

Chinese (China): 绢毛菊属 juan mao ju shuA

Chromosome numbers

Diploids and, rarely, tetraploids, x = 8.B

Bibliography

A. Wu & al., Flora of China 20-21. 2011
B. Watanabe K., Index to chromosome numbers in Asteraceae.