淫羊藿属(小檗科)花瓣的演化和地理分布格局的研究

淫羊藿属的种数与60年前大不相同，现在已知约有50种。该属种类间断地分布于日本至北非 的阿尔及利亚之间的广大地区，这一分布格局表明了该属的古老性质。它们在欧亚大陆的分布极不均 匀，约有80％的种类产于中国中部至东南部，而且根据花瓣的演化分析结果表明，只有中国的淫羊藿属 植物具有连续不断的演化过程。由此可见，中国中部至东南部成为北半球淫羊藿属植物的汇集中心是 有充分根据的。淫羊藿属种类基本上是林地草本植物，常生于水青冈林下，为林下草本层的优势种，而 且该属的分布格局与第三纪植物属——水青冈属在欧亚大陆的分布格局极为相似，说明淫羊藿属植物 在早第三纪时期已广泛分布于北半球。中新世时期由于中亚地区气候变干，加之印度板块向欧亚大陆 俯冲并引起喜马拉雅山脉隆起，致使中亚地区进一步干旱，水青冈属和淫羊霍属植物随之消失，进而导致其东亚—地中海、西亚间断分布格局的形成。

Petal evolution and distribution patterns of Epimedium L.(Berberidaceae)

The genus Epimedium as known at present comprises 50 species, in contrast to the 21 species recognized by Stearn in 1938. Its wide and fragmented range from Japan westward to Algeria indicates its antiquity. The species of the genus Epimedium are far from being evenly distributed over Eurasian land. Approximately 80% species of the total species of the genus are now represented in the central_southeastern China. This must be considered as a very high concentration of the number of species for a genus in a relatively not very large area like that of the central_southeastern China. On the other hand, an analysis of the petal evolution seems to indicate that the genus Epimedium has enjoyed uninterrupted evolution only in China. From the above facts, we can see clearly that the central_southeastern China has the credit of being a center of concentration for the species of Epimedium in the North Hemisphere. Epimedium occupies two widely separated regions, in East Asia and the Mediterranean regions; within each region there are extensive areas from which the genus is entirely absent. Despite the wide and discontinuous distribution outlined above, the ecological requirements of the species appear to be much alike. Essentially woodland herbs, the Epimedium plants often grow in the shade of Fagus forest as dominant species of herb layer in East Asia and the Mediterranean land, and its distribution pattern is very similar to that of Fagus in Eurasian land. It is significant that the distribution pattern of Epimedium coincides in many respects with the modern distribution pattern of the Tertiary genus Fagus. It is reasonable, despite the lack of fossil evidence, to suppose that Epimedium had acquired its wide dispersion in the North Hemisphere during the Paleogene if not before the collision of India with the Eurasia plate and the subsequent uplift of the Himalayas increased aridity in Central Asia. This led to its further disjunction.