作 者 ：Shih Chu
期 刊 ：植物分类学报 1993年 6期
Keywords:Classification,
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 ros-
trum 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 ro-
bust 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, in-
to 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.