J Syst Evol ›› 1993, Vol. 31 ›› Issue (6): 533-548.

• Research Articles • Previous Articles     Next Articles

On the Classification of Ixeris Group (Compositae) from China

Shih Chu   

  • Published:1993-11-18

Abstract: Ixeris Cass., strinctly speaking, is confined to plants which have achenes with sharply winged ribs. Ixeridium (A. Gray ) Tzvel. contains plants which have persistent radical leaves at anthesis and achenes with obtuse ribs and a fine rostrum at its apex. Paraixeris Nakai is restricted to plants which are of the same achenes as in the genus Ixeridium (A. Gray) Tzvel., but rostra of achenes are robust and radical leaves deciduous in flowering in the former. The Chorisis DC., a monotypic genus, is characterized by ternate palatisect leaves. In the light of the above mentioned understanding of these genera, the author thinks that the division of Chinese Ixeris group, a comparatively complex one, into four genera would be more reasonable than merging them into one genus, namely, Ixeris Cass. Based on the examination of specimens in the Herbarium of the Institute of Botany, Academia Sinica (PE), the author found that there are four species in the genus Ixeris Cass., including one new combination in China. They are I. polycephala Cass., I. dissecta (Makino) Shih, I. japonica (Burm. f. ) Nakai and I. stolonifera A. Gray. The genus Ixeridium (A. Gray ) Tzvel. has 13 species, including five new combinations and three new species in China, namely, I. sagittaroides (C. B. Clarke) Shih, I. gramineum (Ledb.) Tzvel., I. yunnarense Shih,I. graminifolium(Ledb.)Tzvel.,I, biparum Shih,I.aculeolatum Shih,I. chinense( Thunb. ) Tzvel., I. strigosum( Fisch. ) Tzvel., I. elegans( Franeh. ) Shih, I. sonchifolium (Maxim.)Shih,I. laevigatum (BI.)Shih,I. dentatum(Thunb. )Nakai and I. gracile(DC.)Shih, in China. There are six species in the genus Paraixeris Nakai, including One new combination, namely, P. denticulata(Houtt.) Nakai, P. humifusa(Dunn) Shih, P. cheldonifolia( Makino) Nakai, P. saxatilis( Baran. ) Tzvel., P.pinnatipartita (Makino)Tzvel. and P.serotina(Maxim.)Tzvel.in China.

Key words: Classification, Ixeris Cass., Ixeridium (A. Gray) Tzvel., Paraixeris Nakai, Chorisis DC., New species, New combinations