Phylogeographic analysis on the endemic vascular plants of the Ryukyus

报道了日本萝摩科植物的染色体数目。形态学和分子系统学研究表明，琉球中部特有种徐长卿（Cynanchum matsumurae）属于娃儿藤属（Tylophora），细胞学和分子系统学研究表明，琉球特有种苦碟子（Ixeris nakazonei）起源于苦碟子（Ixeris repens）和弱苦碟子（I. debilis）的多位种间杂种。本文报道了琉球五节属（Psychotria）和蛇根草属（Ophiorrhiza）的染色体数目。对琉球蛇根草属的分子系统发育分析表明，琉球中部特有种O.japonica var.amamiana是一个孑遗的独立类群;琉球中部特有种E.zigzag是一个孑遗种，与琉球南部特有种E.yaeyamensis不同，而E.emariginata var. minutissima是从E embryata var.本文对琉球中部冲绳岛的卷柏科卷柏属（Selaginellaceae）植物双形卷柏（Selaginellabiformis）与近缘卷柏（S.utchinensis）和刺卷柏（S.davidii）进行了形态学比较。目前的观察表明，报道的刺萼狗牙根是乌特狗牙根，而二型狗牙根与乌特狗牙根的区别不明显。

Chromosome numbers of the family Asclepiadaceae from Japan including the Ryukyus were reported. Morphological and molecular phylogenetic studies showed Cynanchum matsumurae(Asclepiadaceae), an endemic species of the central Ryukyus, belongs to the genus Tylophora.Cytological and molecular phylogenetic studies showed Ixeris nakazonei (Asteraceae), an endemic species of the Ryukyus, derived from polytopic interspecific hybrids between Ixeris repens and I.debilis. Ixeris nakazonei was morphologically and cytologically variable, and the higher polyploid cytotypes of I.nakazonei tend to be distributed in the more southerly area in the Ryukyus.Chromosome numbers of the genera Psychotria and Ophiorrhiza (Rubiaceae) from the Ryukyus were reported. Molecular phylogenetic analysis of the genus Ophiorrhiza of the Ryukyus showed O.japonica var.amamiana, an endemic to the central Ryukyus, is a relict and distinct taxon.Molecular phylogenetic studies on the Eurya(Theaceae) of the Ryukyus showed E.zigzag, an endemic to the central Ryukyus, is a relict species and is distinct from E.yaeyamensis, an endemic to the southern Ryukyus, while E.emariginata var. minutissima is a neoendemic species differentiated from E emarginata var. emarginata on the cloud forests of the central Ryukyus.Morphological comparison of Selaginella biformis, and closely related S.utchinensis and S.davidii (Selaginellaceae) from Okinawa Island, the central Ryukyus, was carried out. The present observation showed the plants reported as S.davidii is S.utchinensis, and the difference of S.biformis and S.utchinensis is not cleaer.