四川贡嘎山地区杜鹃属的地理分布及区系组成

贡嘎山地区位于青藏高原的东南缘,横断山系的东北段,现有杜鹃属植物73种4变种2亚种。在贡嘎山地区东坡的不同垂直高度上分布有43种(包括变、亚种)杜鹃,西坡则分布有63种(包括变、亚种)。贡嘎山地区杜鹃属植物的区系组成属于泛北极植物区,大致分为:1、中国-日本森林植物亚区,只有1种杜鹃。2、中国-喜马拉雅森林植物亚区,有78种(包括4变种, 2亚种),其中(1)1种分布于西藏、云南,并经云南入缅甸分布;(2)44种为四川特产;(3)5种为贡嘎山地区特有种。另外,贡嘎山地区杜鹃属植物区系还有其特点:1、贡嘎山地区是杜鹃属植物分布中心之一;2、贡嘎山地区是杜鹃属植物分化中心之一;3、贡嘎山地区杜鹃属植物有垂直替代现象。

THE GEOGRAPHICAL DISTRIBUTION AND FLORISTIC COMPOSITION OF GENUS RHODODENDRON IN THE GONGGA MOUNTAIN REGION,SICHUAN

The Gongga Mountain Region is located on the eastern fringe of Qinghai-Xizang Plateau and the north-eastern end of Hengduan Mountains. As we know so far the genus Rhododendron in Gongga Mountain Region comprise 2 subgenera and 79 species (including 4 varieties and 2 subspecies) The vertical distribution of the genus Rhododendron in Gongga Mountain Region: Eastern slope: There are 16 species of genus Rhododendron at 1090~2200(2500) m alt. in the subtropical evergreen broadleaf forest zone. At the altitude 2500~3600(~3800) m, in the subalpine coniferous forest zone, found 23 species with 1 variety and 1 subspecies, There are 4 species (including 1 variety and 1 subspecies) at the alpine bush and meadow zone. Western slope: There are 16 species with 1 subspecy at 2300~2800(~3000) m alt., in the river valley shrub zone, at the altitude of 3000~4000m, in the subalpine coniferous forest zone, found 42 species with 2 varieties and 1 subspecies. There are 13 species with 1 subspecies and 1 variety at 4000~4600m alt., in the alpine bush andmeadow zone. The floristic composition of the genus Rhododendron in Gongga Mountain Region. 1. One specy is the elements of the Sino-Japanese Subregion. 2. 78 species (including 4 varieties and 2 subspecies) are the Sino-Himalayan Subregion. (1) One species is distributed to Burna;(2) 44 species (including 4 varieties and 1 subspecies belong to endemic distribution of Sichuan; (3) 5 species are endemic species of Gongga Mountain Region. The floristic characteristics of the genus Rhododendron in Gongga Mountain Region are shown as follows: (1) The Gongga Mountain Region is one of the genus Rhododendron distribution centers. (2) The Gongga Mountain Region is one of the genus Rhododendron differentiation centers. (3) The genus Rhoodendron in Gongga Mountain Region have vertical replacement phenomenon.