横断山区唇形科植物的地理分布

THE GEOGRAPHICAL DISTRIBUTION OF LABIATAE IN HENGDUAN MOUNTAINS

横断山区唇形科植物相当丰富,有46属240种,在国内仅次于云南和四川,但明显多于其它省区。通过对其属、种的分布区类型分析,其地理分布表现如下一些特征;1)从属的分布区类型来说,横断山区唇形科植物主要是温带性质,温带分布区类型的属数占总属数(世界分布的不计算在内,下同)85.3％,其中东亚分布类型为数最多,占总属数34.1％,其次是旧世界分布类型和北温带分布类型,分别占总属数29.2％和12.2％,而东亚分布类型中占绝对优势的是中国喜马拉雅分布亚型。2)从种的分布类型来说,我国特有分布的种占绝大多数,占总种数75％,而温带分布类型和热带分布类型分别占总种数20％和5％。在我国特有分布的种中横断山区特有的占72.8％。在横断山区特有分布的种中滇西北一地特有的占横断山区特有总种数32.1％,川西南一地特有的占横断山区特有总种数9.9％,滇西北和川西南两地共同特有的占横断山区特有总种数25.2％,要是把滇西北川西南看成一整体无疑是横断山区特有种分布中心,占横断山区特有总种数67.2％。3)滇西北川西南特有种分布中心,从其特有种组成分析,其成因有历史的也有生态的,但生态成因多于历史成因,因此该中心的植物区系较为年青,这是由于新构造运动强烈、垂直气候带变化明显,冰川多次进退,导致气候上下位移频繁以?

There are 240 species of 46 genera of Labiatae in Hergduan Mts.,Its species amount is less than that of Yunnan and Sichuan, but muchmore than that of Xizang and other provinces in China. After analysingthe distribution of genera and species of Labiatae in Hengduan Mts., weknow the characteristics of the geographical distribution of Labiatae inthis region as follow:i. The distribution-type of genera is mainly oftemperate nature, having a percentage of 85.3% of total genera. (Thecosmopolitan genera are excluded from the total and from the calculationof the other statics.) Among temperate distributron-type, that of Eastern Asia (mainly of Sino-Himalava subtype) has a percentage 34.1% of totalgeneral and that of Old World temerate and North temperate has a percen-tyge of 29.2% and 12.2% of total genera respectively. ii.The distribution-tupe of species is mainly of endemic in China, having a perceutage of 75%of total species. But that of temperate and tropical only have a percentageof 20% and 5% of total species respectively. Among endemic spceis in Chinaabout a percentage of 72.8% is of endemic in Hengduan Mts. The areaof NW Yunnan and SW Sichuan is a most important center of endemieSpecies is Hengduan Mts. It posscss a percentage of 67.2% of total ende-mic species in Hengduan Mts. iii. The origin cause of endemic species imthe area of NW Yunnan and SW Sichuan is mainly of ecological reasonrather than historical reason.