桂西南珍稀濒危植物区系的研究

桂西南属北热带气候区，面积4．8万km^2，约占全国土地面积的1／200，占广西土地面积的21％，区域内裸露岩溶面积约占50％，。自然分布的国家级珍稀危树种74种，占我国珍稀濒危树种的22．8％，占广西115个珍稀频危树种的64％。其中，龙州一个县分布的珍稀频危树种高达49种，约为全国珍稀频危树种的15％，为广西珍稀濒危树种的42．6％，是全国罕见的珍稀濒危树种荟萃之地。这一地区珍稀濒危树种的植物区系、有独特的地区性、区域内特有的树种明显；有滇、缅、泰地区成分，也有海南地区成分，成为两大地区植物区系交汇之地；更有泛地带性的多种植物，分布有南亚热带、中亚热带、北亚热带以至少数分布暖温带的珍稀濒危树种。研究这一地区珍稀濒危植物区系,大学术、科研以及对珍稀频危树种的保护、发展与利用等方面，均有重要价值。

Study on Rare and Valuble Plant Flora of Southwest of Guangxi,China

In southwest of guangxi ,here are characteristic of north tropical climate zone ,the area range in including 48 000 km 2 ,about 0 5% of the total area of the country and 21% of the total area of Guangxi.In this region,about 50%of the whole area were covered by the exposed calcareous rock,there are 74 species of the rare and valuble plant which wild lived in natrul forest ,about 22 8% species of the rare and valuble species which was on the verge of extinction in the whole China and 64% species of the number of 115 species in Guangxi.In Longzhou,a county town in the rare treasure plant flora region,there are 49 species of the rare and valuble plant in the region,it is holding about 15% of the total number of China and 42 6% of the total muber of Guangxi.It is a exceptional region for rare and valuble plant gather together,there are special regional characteristic,it is a comment boundary region of plant flora with both Xishuangbanna flora and Hainan flora.It is aslo a extrazonal community region,here are distributed rare species of south subtropical zone?centre subtropical zone?north subtropical zone and some fron temperate zone.The studies on the rare plant flora in this special region are very valuble for the rare and valuble plant in conserving?developing and utilizing.