湖南德夯风景区蕨类植物区系的研究

THE STUDY ON PTERIDOPOHYTE FLORA OF DEHANG REGION IN HUNAN

德夯风景区位于湖南省西北部吉首市之西,海拔189.4m-964.6m, 面积252km^2。该区蕨类植物有28科,51属,118种。其特点:(1)、种类丰富而密度大,以鳞毛蕨科、水龙骨科、蹄盖蕨科、卷柏属、铁角属、凤尾蕨属等为优势类群,科内、属内种数贫乏;(2)、属的地理成分以热带成分为主,温带与亚热带成分次之,无特有属。种的地理成分以亚热带成分为主,热带与温带成分次之,特有种类丰富;(3)、东亚成分(尤其是中国-日本成分)众多,可能是东亚成分分布中心的一部分;(4)、与天平山、佼母溪关系最密切,与庐山、黄山、大瑶山关系较密切,与神农架、鼎湖山较疏远。

Dehang region is located at the south of Wuling Mountains, between 28°15'-43'N. ,109°30'-45'E. ,189. 4-964. 6m above sea level. It covers an area of ca. 252km2. After floristic analysis of ferns, we have gained some general conclusions as flowing:(1). Pteridophyts flora is rather rich,there are 118 species belonging to 51 genera and 28 families. It is 46. 83 species /100km2; (2). Species are rare in family and genera,1 -2,3 -4 and 5 or'more species in 53. 57%,17. 88% and 28.57% families respectively;1 - 2,3 - 4 and 5 or more species in 76. 48% ,11. 72% and 11. 80% genera respectively. The main tax-ons are Dryopteidaceae,Palypodiaceae, Athyriaceae and Selaginella,Aspleni-um,Pteris etc. ; (3). The flora is remarkable in sub tropical characteristics. Based on the analysis of geographical composi tions of genera, the results shows that tropical elements are dominaed (62. 75%),but of species, East-Asian elements including Sino -Japan,Sino- Himalaya and Chinese endemic elements are dominaed (80. 53%); (4). The region is a part of the center of East -Asia flora; (5). The flora is much more closely allied to Mt. Tianpin and Giaomoqi region than to the oth ers of its neighourhood, they belong to the Center-China area,Holarctic Kingdom.