中文摘要：

云南中山湿性常绿阔叶林广泛分布于海拔1800~3400 m的山地,这类常绿阔叶林在生态外貌上具有亚热带常绿阔叶林特征,但其分布生境却是暖温带-温带气候,且植物区系组成与热带植物区系有古老的渊源。该文以研究得比较深入的哀牢山中山湿性常绿阔叶林为例,对其植物区系与其气候条件的不协调进行剖析。哀牢山的中山湿性常绿阔叶林记录了种子植物110科386属821种。在植物区系科的地理成分上,无论是含种数多的科,还是所有科的分布区类型,都是以热带分布科为主,体现了它的远古热带起源背景。在该种子植物区系中,热带分布属占总属数的47.75%,热带分布种占总种数的33.45%,在近代演化上仍体现出明显的热带亲缘特征。按照哀牢山中山湿性常绿阔叶林分布地区的暖温带-温带气候条件,它相当于中国东部的暖温带落叶阔叶林地区。在中国东部地区类似气候条件的地带性植被的植物区系中,热带分布属通常只占总属数的25%~27%,云南中山湿性常绿阔叶林植物区系的地理成分与所在地的温带气候明显不协调。对这种现象的解释,笔者认为结合哀牢山地区曾经是低海拔夷平面,在第四纪以来才迅速抬升形成的地质历史,可能这里曾经在第四纪以前的热带-亚热带性质的植物区系和常绿阔叶林随着地形的迅速抬升,逐渐适应了因海拔上升而形成的温带气候,成为在云南高海拔山地存在的所谓中山湿性常绿阔叶林,其植物区系和植被的热带-亚热带性质及常绿阔叶生态外貌并未因气候改变而发生改变。

英文摘要：

Mid-montane wet evergreen broad-leaved forest is widely distributed in the upper montane areas of Yunnan between 1800 ~ 3400 m. This forest has the same ecological and physiognomic characteristics as the evergreen broad-leaved forest of the subtropical lowlands; however,although it has a tropical geographical affinity in its flora,it occurs in warm-temperate to temperate climates. Using the data of a well-studied mid-montane wet evergreen broad-leaved forest in the Ailao Mountains as an example,the apparent disharmony between the forest and the climate where it occurs is discussed. The forest is comprised of 821 seed plant species,belonging to 386 genera in 110 families. In regards to the geographical elements of the flora,tropical families are major contributors,suggesting ancient tropical origin. The tropical distributions make up 47.75% of total genera and 33.45% of total species,strongly suggesting tropical affinity of the flora. The present temperate climate,where themontane wet evergreen broad-leaved forest occurs,is similar to the climate in the eastern regions of China with deciduous broad-leaved forests,in which tropical genera are only minor contributors to the flora. Obviously,the high proportion of tropical elements and the evergreen broad-leaved physiognomy of the forest on the upper montane of the Ailao Mountains exhibit apparent dissonance with the local climate. This might be explained by the rapid uplift of the Ailao Mountains with the Himalayas during the Quaternary period,with the indigenous flora not conspicuously changing although the habitat became a temperate one. Thus, the former evergreen broad-leaved forest found in the tropical / subtropical lowlands has continued in the high montane habitat with the uplift of the terrain.