作 者 ：Fu De-Zhi
期 刊 ：植物分类学报 1988年 4期
Keywords:Dichocarpum, Pollen, Chromosome number, System, Classification, Distribution,
Abstract:
The genus Dichocarpum was established by W. T. Wang and Hsiao in 1964, who
divided the genus into 2 sections: Sect. Dichocarpum including 10 species distributed on the
mainland of E. Asia, and Sect. Hutchinsonia including 9 species native to Japan. M. Tamura
and L. A. Lauener made a revision of the genus in 1968, who divided the genus into 4 sec-
tions, three for the species of the mainland of E. Asia, including 3 series and 10 species, and
the other for the species of Japan, including 2 subsections, 3 series and 9 species. In the pre-
sent paper, the genus is divided into 2 sections and 6 series, including 15 species and 3 varie-
ties, and a putative phylogeny of the genus is proposed. The genus may be close to the genus
Asteropyrum, and these two genera are rather specialized in Thalictroides (Ranunculaceae),
because they have three very similar characters: the petal with a long claw, the stephanocolpate
pollen and the chromosome morphology. The genus has 2n=24, 35(36?), which indicates that
its basic number is X=6, and the species on the mainland of E. Asia (Sect. Dichocarpum)
may well be paleotetraploids, whereas those in Japan (sect. Hutchinsonia) are paleohexap-
loids. Most of the advanced species are distributed in Japan and the most primitive ones in
China and the Himalayas, the distribution pattern seggests that the Japanese members of this
genus might have immigrated from China in the Tertiary, and differentiated and evolved
there. The putative phylogeny of the genus is shown in Fig. 2 (at series level)