西双版纳勐宋热带山地雨林种子植物区系的初步研究

西双版纳勐宋的热带山地雨林是一种东南亚热带山地雨林的北缘类型,它在植物区系组成上和群落学特征上是介于热带雨林和南亚热带常绿阔叶林之间的热带山地常绿阔叶林.该区系有种子植物116科327属623种.科、属、种的分布区类型分析表明:科的分布区类型以热带和亚热带分布最多(32.8%),其次是热带到温带分布(23.3%)和典型热带分布(18.1%);属的分布区类型以热带亚洲分布最多(28.4%),其次是泛热带分布(26.8%),热带分布多于温带分布(258:55);种的分布区类型以热带亚洲分布最多(65.0%),其次是中国特有分布(26.5%),热带分布远多于温带分布(431:18).区系的热带性质显著,具有明显的印度-马来西亚植物区系特点,属于热带亚洲区系的一部分.由于特殊的地理位置,西双版纳地区是许多典型热带植物的分布北界,同时又是几种热带成分的交汇地带.

A Study on the Flora of Seed Plants of Tropical Montane Rain Forest in Mengsong, Xishuangbanna

A tropical montane rain forest was investigated in Mengsong, south-west to Jinghong City ofXishuangbanna region in the south of Yunnan near the border between China and Myanmar. There are 623 species of seed plants belonging to 327 genera and 116 families in this forest. Analysis of areal types shows that 32.8% of the families are of tropical and subtropical type, 23.3% tropical to temperate type, and 18.1% typically tropical type. Areal types at generic level mostly are tropical (81.4%), in which 28.4% are of Indo-Malaysian type and 26.8% are of pantropic type. The ratio of tropical to temperate genera is 258: 55. As for specific rank, the elements of tropical Asia type reaches 65.0%, and that of endemic to China 26.5%. The number of tropical species (431 species) is far more than the temperate ones (18 species). It is concluded that this flora is tropical in nature with obvious characteristics of Indo-Malaysia flora. It is a transitional area of tropics to subtropics, and is the north distribution limits for many typically tropical plants.