中文摘要：

在中国植物学文献中,对热带季雨林的解释和运用是不一致的,特别是易于把季雨林与热带雨林相混淆。季雨林是在具有明显干、湿季变化的热带季风气候下发育的一种热带落叶森林植被,是介于热带雨林与热带稀树草原（savanna）之间的一个植被类型。云南的热带季雨林在分布生境、生态外貌特征、植物种类组成和地理成分构成上,均与热带雨林有明显区别,季雨林主要分布在海拔1000m以下的几大河流开阔河段两岸和河谷盆地,其群落结构相对简单,乔木一般仅有1至2层,上层树种在干季落叶或上层及下层树种在干季都落叶;在生活型组成上,季雨林的木质藤本相对较少,大高位芽植物及地上芽植物很少,但地面芽植物很丰富,地下芽植物和一年生植物也相对丰富;在叶级和叶型特征上,季雨林植物的小叶和复叶比例相对较高,分别占到24%和44%;在植物区系地理成分构成上,季雨林的热带分布属合计也占绝对优势,但以泛热带分布属的比例相对较高,约占到总属数的30%,热带亚洲至热带非洲分布属的比例也较高,约占总属数的12%。季雨林的地理成分更为多样性,起源与发展历史也更复杂和古老。

英文摘要：

In Chinese botanical literature,the term ＂tropical monsoon forest＂ is explained and used inconsistently and is of-ten confused with tropical rain forest.My objective is to clarify differences between the two forests.Schimper defined tropical monsoon forest as being more or less leafless during the dry season and considered it a transi-tional vegetation type between tropical rain forest and savanna in terms of physiognomy and distribution.I com-pared tropical monsoon forest and rain forest in physiognomy,floristic composition and geographical elements to describe and characterize the monsoon forest in Yunnan,China.The tropical monsoon forest in Yunnan occurs mainly on river banks and in basins of several large rivers below 1 000 m altitude.The forest has one or two tree layers,and trees of at least the top layer are deciduous in the dry season.In life forms,the forest is rich in hemicryptophytes and relatively rich in geophytes and therophytes,but less rich in woody lianas and almost lacks megaphanerophytes and chamaephytes compared to tropical rain forest.In leaf size and form,the forest has more microphyllous leaves and compound leaves （24% and 44% of tree species,respectively） than tropical rain forest.In terms of floristic elements,the forest has a greater percentage of species of pantropic distribution （30% of the genera） and tropical Asia and tropical Africa disjunct distribution than tropical rain forest.Thus,the tropical mon-soon forest in Yunnan has more diverse geographical elements in its flora and a complicated evolution history.