湖南省德夯风景区蕨类植物区系的研究

THE STUDY ON PTERIDOPHYTE FLORA OF SCENIC SPOT IN DEHANG, HUNAN

德夯风景区位于湖南省西北部吉首市之西。海拔１８９．４～９６４．６ｍ，面积２５２ｋｍ２。该区蕨类植物有２８科，５１属，１１８种，区系特点是：（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（Ｓｅｌａｇｉｎｅｌｌａ），铁角蕨属（Ａｓｐｌｅｎｉｕｍ），凤尾蕨属（Ｐｔｅｒｉｓ）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, from 189.4 m. to 964. 6 m.above sea level. It covers an area of ca. 252 km2.After floristic analysis of ferns, some general conclusions are gained as flowing: (1)Pteridophyte flora is rather rich, there are 118 species belonging to 51 genera and 28 families. It is 46. 83 species Per hundred square kilometre, (2) Species are rare in family and genera, 1 or 2 species in 53.57% families; 3 or 4 species in 17.88% families; 5 or more species in 28.57% families; 1 or 2species in 76.48% genera, 3 or 4 species in 11.72% genera and 5 or more species in so genera. The main taxons are Dryopteridaceae. Polypodiaceae. Athyriaceae and Selaginella, Asplenium、Pteris etc; (3) The flora is remarkable in subtropical characteristics. Based on the analysis of geographic compositions of genera, the results shows that tropical elements.are dominant (62.75%),but of species, East-Asian elements including China-Japan & China-Himalaya and Chinese endemic elements are dominant (48.67% and 31.86%); (4) the region is a part of the center of East-Asian elements, (especially China-Japan element), and it is also a key area of East-Asian flora; (5) The flora is much more closely allied to Tianpin Mt. and Giaomoqi region than to the others of its neighbourhood, they belong to the Center-China area, Holarctic Kingdom.