试论东亚被子植物区系的历史成分和第三纪源头——基于省沽油科、刺参科和忍冬科植物地理的研究

ON HISTORICAL ELEMENTS AND TERTIARY PRECURSORS OF EASTERN ASIATIC ANGIOSPERMOUS FLORA——BASED ON PHYTOGEOGRAPHY OF STAPHYLEACEAE,MORINACEAE AND CAPRIFOLIACEAE

虽然在历史植物地理学文献中常见的有5种区系成分:地理成分、发生成分、迁移成分、历史成分和生态成分,但由于缺乏古地理、古气候和古植物资料,当前要全面分析一个区系中所有5种成分是不可能的。本文是基于省沽油科、刺参科和忍冬科植物研究的结果,企图分析东亚植物区系的历史成分,从一个侧面看到它的演变过程。除去本地产生的鬼吹箫属和六道木属之外,凡以上3科在东亚有分布的属,按其历史成分,可归为3类:北方第三纪成分——忍冬属、猬实属、锦带花属和莛子藨属;提特斯第三纪成分——刺参属、刺续断属、蓟叶参属、野鸦椿属、毛核术属、糯米条属、北极花属、双盾木属和七子花属;北热带成分——山香圆属、省沽油属和瘿椒树属。本文所指北方第三纪植物群和提特斯第三纪植物群是采用Takhtajan的概念,而北热带植物群是采用Wolfe的概念。这3种成分意味着东亚被子植物区系在演变过程中有3个第三纪源头。本文作者还认为中新世在东亚植物区系中似可作为区分被子植物“新特有属”和“古特有属”的一个分界期。大凡起源于中新世以前的属可视为“古特有属”,起源于中新世及其后的可归为“新特有属”。这个假设是基于下列理由:(1)东亚植物区系的主体部分形成于早中新世;(2)在中新世,植物长距离的传播基本停止。

Although five types of floristic elements are generally recognized in the historical plant geography, namely geographical element, genetic element, migration element, historical element and ecological element, it is impossible to analyze all of them because of insufficiency of paleogeographical, paleoclimatic and paleobotanical data now. In this paper an attempt is made to present one aspect of the florogeny of eastern Asiatic flora based on an analysis of the historical elements of Staphyleaceae, Morinaceae and Caprifoliaceae. All the genera but autochthonous Leycesteria and Zabelia belonging to the three aforementioned families and distributed in this interesting floristic region are tentatively grouped into threecategories; the boreal Tertiary element——Lonicera, Kolkwitzia, Weigela and Triosteum;the Tethyan Tertiary element——Acanthocalyx, Marina, Cryptothladia, Euscaphis, Sym-pharicarpos, Abelia, Linnaea, Dipelta and Heptacodium; and the boreotropical element——Turpina, Staphylea and Tapiscia. Takhtajan's concepts of the boreal Tertiary flora and the Tethyan Tertiary flora are followed here, while the conception of boreotropical flora is just the same as that of Wolfe. It means that eastern Asiatic angiospermous flora has three Tertiary precursors. In the present paper the Miocene is theoretically considered to be a period forming the division between paleoendemic and neoendemic genera of flowering plants in eastern Asiatic flora. In general, the genera appearing before the Miocene are recognized as paleoendemic, while those appearing in and after the Miocene neoendemic. This is based on the following presumptions: (1) The main body of eastern Asiatic flora seems to be formed in the early Miocene. (2) In the Miocene long dispersal might no longer play an important part of plant migration. Since then the world flora probably underwent a great differentiation and the different local floras were greatly enriched by rapidly developed endemic groups. (3) From the Miocene to the Pliocene the Himalayan movement was intensified. Not only did the movement drastically affect the geornorphological features, but also greatly changed the whole natural environment of China.