台湾岛和海南岛兰科植物区系特征比较

为探明台湾岛和海南岛兰科( Orchidaceae)植物区系特征,在充分查阅相关资料的基础上,对2个岛屿兰科植物的物种组成、生活型和分布区类型进行分析,并对这2个岛屿与大陆陆地和周边国家兰科植物的分布特征进行比较和分析。结果表明：2个岛屿的兰科植物共有146属639种,其中,台湾岛有107属446种,海南岛有96属302种。2个岛屿树兰亚科( Subfam. Epidendroideae)的属和种比例均最高；原始的拟兰亚科( Subfam. Apostasioideae)在台湾岛无分布,而在海南岛分布有2属4种。从属和种的数量看,含1种和2~5种的属比例较高,分别占台湾岛兰科植物总属数的43.9%和36.4%,占海南岛兰科植物总属数的45.8%和40.6%；且包含种数多的属的比例较低。从生活型看,2个岛屿地生兰和附生兰的比例较高,分别占台湾岛兰科植物总种数的52.7%和34.3%,占海南岛兰科植物总种数的37.1%和55.3%。从分布区类型看,台湾岛和海南岛的兰科植物分别可划分为11和10个分布区类型,且均以热带亚洲至热带大洋洲分布型属和种的比例最高,热带亚洲分布型属和种的比例也较高。从热带成分与温带成分的数量比(R/T)看,台湾岛和海南岛兰科植物属的R/T值分别为3.6和3.3,种的R/T值分别为10.9和11.9,说明2个岛屿的兰科植物均以热带成分为主,台湾岛还包含一定的温带成分。从共有属和共有种看,2个岛屿与大陆陆地的兰科植物共有属均约占各自兰科植物总属数的90.7%,其中,三地共有属有66属；台湾岛与大陆陆地的兰科植物共有种比例较低(46.2%),而海南岛与大陆陆地的兰科植物共有种比例较高(74.9%),说明2个岛屿与大陆陆地兰科植物属的同源性较高,且海南岛兰科植物的大陆性特征更明显。与周边国家相比,2个岛屿与越南的兰科植物共有种比例较高,分别占台湾岛和海南岛兰科植物总种数的33.9%和75.2%。综合分析结果显示：台湾岛和海南岛的兰科植物种类丰富,生活型齐全,且具有明显的热带性质,但台湾岛的兰科植物还表现出一定的温带性质；2个岛屿与大陆陆地兰科植物的亲缘关系较近,但台湾岛兰科植物的特有性更明显。

Comparison on floristic characteristics of Orchidaceae on Taiwan Island and Hainan Island

In order to verify floristic characteristics of Orchidaceae on Taiwan Island and Hainan Island, on the basis of full consulting to related data, species composition, life-form and areal-type of Orchidaceae on two islands were analyzed, and comparison and analysis on distribution characteristics of Orchidaceae on the two islands with land of mainland China and surrounding countries were carried out. The results show that there are totally 639 species belonging to 146 genera of Orchidaceae on two islands, in which, there are 446 species belonging to 107 genera on Taiwan Island, and 302 species belonging to 96 genera on Hainan Island. Percentages of genus and species of Subfam. Epidendroideae on two islands all are the highest. Subfam. Apostasioideae which is the original subfamily doesn’ t distribute on Taiwan Island, while there are 4 species belonging to 2 genera distributed on Hainan Island. In view of numbersof genus and species, percentages of genus containing 1 species and 2-5 species are higher, accounting for 43 . 9% and 36 . 4% of total number of genus on Taiwan Island and 45 . 8% and 40 . 6% of total number of genus on Hainan Island, respectively, and percentage of genus containing many species is lower. In view of life-form, percentages of terrestrial and epiphytic orchilds on two islands are higher, accounting for 52 . 7% and 34 . 3% of total number of species on Taiwan Island and 37 . 1% and 55 . 3%of total number of species on Hainan Island, respectively. In view of areal-type, Orchidaceae on Taiwan Island and Hainan Island can be divided into 11 and 10 areal-types, respectively, and percentages of genus and species belonging to Trop. Asia & Trop. Australasia areal-type are the highest, those belonging to Trop. Asia areal-type are also higher. In view of ratio of tropical element number to temperate element number ( R/T) , R/T values of genus in Orchidaceae on Taiwan Island and Hainan Island are 3. 6 and 3. 3, respectively, those of species are 10. 9 and 11. 9, respectively, meaning that Orchidaceae on two islands are mainly tropical element, and Taiwan Island also contains a certain temperate element. In view of common genera and common species, common genera in Orchidaceae on two islands with land of mainland China both account for about 90 . 7% of their respective total number of genera in Orchidaceae, in which, there are 66 genera of common genera in three lands. Percentage of common species in Orchidaceae on Taiwan Island and land of mainland China is lower (46. 2%), while that on Hainan Island and land of mainland China is higher (74. 9%), meaning that homology of genera in Orchidaceae on two islands with land of mainland China is higher, and continental characteristics of Orchidaceae on Hainan Island are more obvious. Compared with surrounding countries, percentages of common species in Orchidaceae on two islands and Vietnam are higher, accounting for 33. 9% and 75. 2% of total number of species in Orchidaceae on Taiwan Island and Hainan Island, respectively. The result of comprehensive analysis indicates that species in Orchidaceae on Taiwan Island and Hainan Island are rich with complete life-form and obvious tropical property, but Orchidaceae on Taiwan Island also appears a certain temperate property. Relationship of Orchidaceae on two islands with land of mainland China is closer, but endemicity of Orchidaceae on Taiwan Island is more obvious.