Crepidiastrum

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Description

Herbs, annual, biennial, or perennial, sometimes subshrubs, often rosulate, with a taproot. Stems usually leafy. Leaves undivided or pinnately lobed; stem leaves often clasping. Capitula with 5–20 florets. Involucres narrowly cylindric. Phyllaries with narrow scarious margin; outer phyllaries few, longest ca. 1/4(–1/2) as long as inner ones; inner phyllaries 5 or 8, linear-lanceolate, equal in length. Receptacle naked. Florets yellow. Achene ± fusiform, slightly compressed, with 5 main ribs alternating with 1 or 2 secondary ribs, usually scabrid of antrorse acute papillae especially toward apex, rarely glabrous or muriculate, apex attenuate or with a beak less than 1/5 or to 1/2 of achene length. Pappus white, scabrid, usually ± caducous.

from: Shih C. & Kilian N. in Wu Z. Y. & al. (ed.), Flora of China 20–21: 264. 2011, Beijing & St Louis.

Distribution

Asia-Temperate: Afghanistan (Afghanistannative); Altay (Altaynative); Amur (Amurnative); Buryatiya (Buryatiyanative); China North-Central (Gansunative, Hebeinative, Shaanxinative, Shandongnative, Shanxinative); China South-Central (Chongqingnative, Guizhounative, Hubeinative, Sichuannative, Yunnannative); China Southeast (Anhuinative, Fujiannative, Guangdongnative, Guangxinative, Henannative, Hunannative, Jiangsunative, Jiangxinative, Zhejiangnative); Chita (Chitanative); Inner Mongolia (Nei Mongolnative); Irkutsk (Irkutsknative); Japannative (Hokkaidonative, Honshunative, Kyushunative, Shikokunative); Kazakhstan (Kazakhstannative); Khabarovsk (Khabarovsknative); Kirgizistan (Kirgizistannative); Koreanative (North Koreanative, South Koreanative); Krasnoyarsk (Krasnoyarsknative); Manchuria (Heilongjiangnative, Jilinnative, Liaoningnative); Mongolianative (Mongolianative); Nansei-shoto (Nansei-shotonative); Ogasawara-shoto (Ogasawara-shotonative); Primorye (Primoryenative); Tadzhikistan (Tadzhikistannative); Taiwan (Taiwannative); Tibet (Tibetnative); Tuva (Tuvanative); West Siberia (West Siberianative); Xinjiang (Xinjiangnative); Yakutskiya (Yakutskiyanative) Asia-Tropical: Assam (Assamnative); India (Uttar Pradeshnative); Laos (Laosnative); Nepal (Nepalnative); Philippines (Philippinesnative); Vietnam (Vietnamnative); West Himalaya (Himachal Pradeshnative, Jammu-Kashmirnative)

Systematics

Pak & Kawano (1990a, b, c, 1992) concluded from their their carpological and cytological investigations that Paraixeris cannot be separated from Crepidiastrum. This has been confirmed through a molecular phylogenetic analyses by J. W. Zhang & al. (in prep.), on which the treatment by Shih & Kilian (in Shih & al. 2011) is based. The analyses by J. W. Zhang & al., moreover, revealed that the Youngia segregate Crepidifolium is also nested within the Crepidiastrum clade, thus confirming an earlier assumption by Sennikov (1997), which Sennikov later revised in favour of establishing the separate genus Crepidifolium (Sennikov & Illarionova 2008). Crepidifolium is therefore also best treated as a congener of Crepidiastrum, extending the geographical range of the latter genus to Central Asia.

Crepidiastrum in this wider sense, as treated by Shih & Kilian (in Shih & al. 2011), has been corroborated through a more recent molecular phylogenetic analysis by Peng & al. (2014), with the single exception that the hitherto little known C. humifusum actually is a member of Youngia. Crepidiastrum in this revised sense includes about 14 species with a basic chromosome number of x = 5 and is distributed in Central and E Asia, including including N Pacific Bonin (Ogasawara) Islands.

References


Pak J.-H. & Kawano S. 1990a: Biosystematic studies on the genus Ixeris and its allied genera (Compositae-Lactuceae) I. Fruit wall anatomy and its taxonomic implications. – Acta Phytotax. Geobot. 41: 43–60.

Pak J.-H. & Kawano S. 1990b: Biosystematic studies on the genus Ixeris and its allied genera (Compositae; Lactuceae) II. Karyological analyses. – Cytologia 55: 553–570.

Pak J.-H. & Kawano S. 1990c: Biosystematic studies on the genus Ixeris and its allied genera (Compositae - Lactuceae) III. Fruit wall anatomy and karyology of Crepidiastrum and Paraixeris, and their taxonomic implications. – Acta Phytotax. Geobot. 41: 109–128.

Pak J.-H. & Kawano S. 1992: Biosystematic studies on the genus Ixeris and its allied genera (Compositae; Lactuceae) IV. Taxonomic treatments and nomenclature. – Mem. Fac. Sci. Kyoto Univ., Ser. Biol. 15: 29–61.

Peng Y.-L., Zhang Y., Gao X.-F., Tong L.-J, Li L., Li R.-Y., Zhu Z.-M. & Xian J.-R. 2014: A phylogenetic analysis and new delimitation of Crepidiastrum (Asteraceae, tribe Cichorieae). – Phytotaxa 159: 241–255. // ➪ //

Sennikov A. N. 1997: Kriticheskie zametki o vidakh podtrib Lactucinae i Crepidinae (Asteraceae, Lactuceae) Mongolii, Kitaya i V'etnama [Critical notes on the species of the subtribes Lactucinae and Crepidinae (Asteraceae, Lactuceae) from Mongolia, China and Vietnam]. – Bot Zhurn. 82(5): 110–117.

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.

Common names

Chinese (China): 假还阳参属 jia huan yang shen shuA

Chromosome numbers

Diploids, triploids and tetraploids, x = 5.B

Bibliography

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