Ixeridium

Primary tabs

Ixeridium

Common names

Chinese (China): 小苦荬属 xiao ku mai shu A

Systematics

Ixeridium is a genus of about 15 species, distributed in E and SE Asia. The circumscription of Ixeridium employed here follows Pak & Kawano (1992), based on carpological and karyological investigations, and Shih & Kilian (in Shih & al. 2011), based on molecular phylogenetic analyses of subtribe Crepidinae by J. W. Zhang & al. (in prep.). The placement by the latter authors of the two little-known species with a white pappus, I. aculeolatum and I. sagittarioides is, however, explicitly stated as being tentative, because otherwise the genus only comprises species with a yellowish or straw-coloured pappus. Its basic chromosome number is x = 7. An ITS phylogeny by Nakamura & al. (2014) did not include the critical species with white pappus but otherwise confirmed this concept of Ixeridium, and also showed its sister group relationship to Ixeris.

References

Nakamura K., Chung S.-W., Kono Y., Ho M.-J., Hsu T.-C. & Peng C.-I 2014: Ixeridium calcicola (Compositae), a new limestone endemic from Taiwan, with notes on its atypical basic chromosome number, phylogenetic affinities, and a limestone refugium hypothesis. \u2013 PLoS ONE 9(10): e109797. // ➪//

Pak J.-H. & Kawano S. 1992: Biosystematic studies on the genus Ixeris and its allied genera (Compositae: Lactuceae): 4. Taxonomic treatments and nomenclature. – Mem. Fac. Sci. Kyoto Univ., Ser. Biol. 15: 29–61.

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.

Description

Herbs, perennial, often rosulate. Stem ascending-erect to erect, branched from base or higher up. Synflorescence usually corymbiform or paniculately corymbiform, with few to many capitula. Capitula with 5–11(–18?) florets. Involucre narrowly cylindric. Phyllaries in few series, margin narrow and scarious; outer phyllaries few, very short (at most ca. 2 mm, usually less), ± unequal; inner phyllaries 5 or (7 or)8, linear-lanceolate, equal. Receptacle naked. Florets some shade of yellow [or rarely white]. Achene pale brown to brown, usually ± subfusiform, subcompressed, with 5 slender main ribs alternating usually with 1 (only exceptionally with 0 or 2) narrower to subequal secondary ribs, space between ribs widely U-shaped, apically often with antrorse acute papillae, apex attenuate into a short slender beak. Pappus yellowish to straw-colored or rarely ?white, of scabrid bristles.

from: Shih C. & Kilian N. in Wu Z. Y. & al. (ed.), Flora of China 20–21: 328. 2011, Beijing & St Louis.

Chromosome numbers

Diploids, triploids and tetraploids, x = 7.B

Distribution

Asia-Temperate: China North-Central (Gansu native: presence questionable, Hebei native: presence questionable, Shaanxi native: presence questionable, Shandong native); China South-Central (Chongqing native, Guizhou native, Hubei native, Sichuan native, Yunnan native); China Southeast (Anhui native, Fujian native, Guangdong native, Guangxi native, Hunan native, Jiangsu native, Jiangxi native, Zhejiang native); Hainan native; Japan (Hokkaido native, Honshu native, Kyushu native, Shikoku native); Korea native; Kuril Is. native; Manchuria (Heilongjiang native: presence questionable, Jilin native: presence questionable, Liaoning native: presence questionable); Nansei-shoto native; Taiwan native; Tibet native; Transcaucasus (Adzhariya introduced, Azerbaijan introduced) Asia-Tropical: Assam (Assam native, Manipur native, Meghalaya native); Borneo (Sabah native); Cambodia native; East Himalaya (Arunachal Pradesh native, Bhutan native, Darjiling native, Sikkim native); India (Uttar Pradesh native, West Bengal native: presence questionable); Jawa native; Laos native; Maluku native; Myanmar native; Nepal native; New Guinea (Irian Jaya native, Papua New Guinea native); Pakistan native; Philippines native; Sulawesi native; Thailand native; Vietnam native; West Himalaya (Himachal Pradesh native, Jammu-Kashmir native, Uttaranchal native)

Bibliography

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