中国植物区系中的特有性及其起源和分化

Origin and Differentiation of Endemism in the Flora of China

对中国植物区系中的239个特有属,分属67个科,进行了分析研究,列出了这些特有属在种子植物各个科的分布,现代地理分布范围。结果表明含特有属在10个以上的有5个科即Gesneriaceae,Compositae,Labiatae,Cruiciferae,Umbelliferae;其中以Gesneriaceae居榜首(27属),Compositae位居第二(20属),Labiatae有12属,居第三。含2属的科有15个,含1属的科有30个;其中Ginkgaceae,Davidiaceae,Eucommiaceae,Acanthochlamydaceae组成了中国植物区系最具古老性、特有性和代表性的4个单型科。在此基础上,从特有属在被子植物八纲系统各个纲的分布特点,以及在各个科组成和系统关系及已有地质、化石历史和系统学,形态,分子证据论述了这些特有属的起源、系统关系及在植物地理上的关系。在裸子植物中,特有属最为丰富,几乎皆是地质历史上北极-第三纪成分的残遗,起源时间较早,可追溯到白垩纪或更早。被子植物中,中国特有属存在于八纲被子植物的所有纲中,几乎在现代被子植物各个演化阶段均有古老残遗的特有类群存在,同时也不乏新特有类群尤其是在演化的高级阶段的类群。从起源上看,被子植物的古特有属主要发生于晚白垩纪和早第三纪,地质历史上大都占有广阔的分布区;新特有属多发生在新第三纪以后。其源头主要是北极第三纪、古热带第三纪(冈瓦纳第三纪)和古地中海第三纪的奇妙结合,不少类群是就地起源的;特有性是在第三纪中晚期以后北半球气候变迁,迁移途径(如北大西洋陆桥和白令陆桥)中断后形成的,这一时期是我国特有属形成发展的起始标志。

The paper analyzed 239 endemic genera in 67 families in the flora of seed plants in China. The results showed that there are five families containing morn than ten endemic genera, i.e., Gesneriaceae （27, number of endemic genera in China, same thereafter）, Composite （20）, Labiatae （12）, Crucfferae （11）, and Umbelliferac （10）, 15 families with two endemic genera, and other 30 families with only one endemic genus. Four monotypic families, i.e., Ginkgoaceae, Davidiaceae, Eucommiaceae and Acanthochlamydaccae, are the most ancient, relic and characteristic in the flora of seed plants in China. Based on integrative data of systematics, fossils histories, morphological and molecular evidence of these genera, their origination, evolution and relationships were discussed. In gymnosperms, all endemic genera are relics of the Arctic-Tertiary flora, having earlier evolutionary history, and can be traced back to the Cretaceous or to the Jurassic and even earlier. In angiosperms, the endemic genera are mostly relic, and are represented in all lineages in our Eight-Class System of classification of angiosperms, and endemism can be found in almost every evolutionary stage of extant angiosperms. The relic genera once occupied huge areas in North Hemisphere in the Tertiary or the late Cretaceous, while neo-endemism was mostly originated in the late Tertiary. They canoe from Arctic-Tertiary, Paleo-tropical-Tertiary and Tethys-Tertiary florisitic dements and the blend of the three dements, with many genera of autochthonous origination. The endemism was formed when some dispersal route such as the North Atlantic Land Bridge, and the Bering Bridge became discontinuous during the Tertiary, as well as the climate change and glaciation in the late Tertiary and the Quaternary. Therefore, the late Tertiary is the starting point of extant endemism of the flora of China.