德夯风景区植物区系的研究(Ⅱ)地理成分及其起源分析

A Study of Rloral in Dehang Region (Ⅱ) an Analysis on Geographical Elements and Its Origins

对湖南省吉首市德夯地区514个野生种子植物属统计分析，结果表明：（1）该区植物区系主要由中小型属组成，属内种数贫乏，少型属与单型属占有一定比例；（2）含我国15种地理成分的14种，其中以北温带分布，泛热带分布，热带亚洲分布，东亚—北美分布及东亚分布5种成分为代表，尤以后4者最为重要；（3）起源复杂，有自古南大陆和古北陆南部起源后向北迁移来的热带成分，有自高纬度大陆起源后南移来的温带成分，也有我国亚热带就地起源的亚热带成分。这里的热带性质与温带性质并不明显，而亚热带性质十分突出，表明该区庆典型的亚热带植物区系。

Based on the statistical analysis on 514 genera of seed-plant in Dehang, this paper re-veals that: (1 )The flora consists mainly of the middle- small genus with a litt1e species; (2)There are 14 areal -types of 15 geographical elements in our country toldly, in which 5 types(North Temperate 'Pantropic . Trop. Asia . E. asia -N. Amer. disjuncted and E. Asia )are dom-inant,especially the later 4 types are more important in maintaining the fauction of the floraand regetations; (3)In the flora,tropic elements maybe from Gondwana and south Laurasia;temperate elememts maybe from high latitudes area and subtropic elements may originatefrom the subtropic area including Dehang in our country. It is quite clear that the flora is atypical case of subtropicaI in our country.