槭属的系统演化与地理分布

槭属（ＡｃｅｒＬ）属槭树科（Ａｃｅｒａｃｅａｅ），２００种，分布于亚、欧、北美和非洲北缘。本文研究了槭属的系统演化、地理分布、起源与扩散。认为：（１）槭树科与无患子科关系密切，槭属是槭树科２属中较进化的类群。（２）在原始而典型的槭属植物的基础上，槭属沿花的各部减少，有的器官甚至向完全退化的方向演化，但也有少数向增加数目的方向特化。（３）讨论了槭属４亚属２３组的演化趋势，并绘制出其系统演化图。（４）槭属起源于侏罗纪的中国四川东部、湖北、湖南及其邻近地区，并向西、东北和南方扩散而进入西亚、欧洲、非洲北缘、北美洲和马来半岛至印尼。

The Systematic Evolution and Distribution of the Genus Acer

The genus Acer L. contains 200 species and is distributed in Asia, Europe, N Africa and N America, especially the Yangtze River Valley probably is a distribution center. The systematic evolution, origin and spread of Acer are discussed. The following hypotheses are suggested. (1) The Aceraceae is closely related Sapindaceae. The Acer L. is advanced genus in Aceraceae. (2) Based upon the primitive and typical plants, some plants of the genus Acer were evolved in direction of reduction or even of entire degeneration of the elements of flower, some others were specialized by increasing of the elements of flower. (3) The evolutionary relationship of the four subgenera and twenty three sections of Acer are discussed. A figure showing their evolutionary relationship is provided. (4) The plants of Acer were found in the Jurassic in E Sichuan, Hubei, Hunan and neighbourhood in China, then spread to W Asia, Europ, N Africa and N America.