Study On The Flora Of Seed Plants In The Limestone Mountain Of Jiangyong And Fuchuan Four Counties Of Hunan-Guangxi Border Region

The seed plant flora in the limestone mountainous of Jiangyong,Jianghua,Fuchuan and Guanyang was systematically studied and analyzed.The seed plant flora character and the relationship and origin with related plant flora were discussed.The following results were obtained:1.The basic composition of floraAccording to the survey,there are 108 families,241 genera and 387 species of seed plants in the limestone of Jiangyong,Jianghua,Fuchuan and Guanyang.The family including less genus(57 families,52.78%),and one species dominated(59 families,54.63%).The genus including one species(157 genera,65.15%)and less species(81 genera,33.61%)dominated.2.The floristic characteristics and natureThere are 108 families of seed plants in the limestone mountainous of Jiangyong,Jianghua,Fuchuan and Guanyang can be classified into 8areal types and 8 subtypes,including tropical composition 61 families,accounting for 74.39% of total number,temperate composition 21 families,accounting for 25.61% of total families.This place of seed plants belonging to 241 genera can be classified into 14 areal types and11 subtypes,of which pantropical distribution(54 genera,accounting for23.89%),tropical Asia distribution(29 genera,accounting for 12.83%),north temperate distribution(21 genera,accounting for9.29%),discontinuous distribution in east Asia and North America(18genera,accounting for 7.97%)accounts for a bigger proportion of shows the limestone mountain seed plants flora and the close related between these places.This limestone mountain area include tropical genera 143 genera,accounting for 59.34% of the total genera,temperate genera 83 genera,accounting for 34.44% of the total genera.The tropical composition is higher than the temperate composition,has the nature of the flora of south of China tropical north rim.3.Floristic originThe seed plant flora in the limestone mountainous of Jiangyong,Jianghua,Fuchuan and Guanyang is influenced by many kinds of components because of its unique geographical location,so the composition of the flora is very complicated,although affected by the south China flora,dianqiangui flora and central China flora,but it is mainly affected by the flora of Southern China,that is the extension of south of China flora.4.To divide limestone endemic plantsThrough investigation and study on limestone mountainous multiple caves of Jiangyong,Jiang Hua,Fuchuan and Guanyang,the limestone cave plants can be divided into three types,namely limestone cave exclusive species,limestone cave suitable species and limestone caveaccidental species.Results show that there are limestone cave exclusive species 4,suitable species 11,accidental species 40.5.Conservation of plant diversity in limestoneThere are endangered plants 11 species in the limestone mountainous of Jiangyong,Jianghua,Fuchuan and Guanyang,there are 3 kinds of Endangered plants,4 Vulnerable plants,4 kinds of Near Threatened plants according to the IUCN evaluation criteria.On the basis of the available information and field survey,It is suggested that some rare and endemic species of limestone plants be included in the list of rare and endangered plants.We also analyses of the causes of plant endangered in this region,and put forward the protection strategy of them.6.New discovery of floristicStudy on the seed plant flora in the limestone mountainous of Jiangyong,Jianghua,Fuchuan and Guanyang found 1 new species,1new record of plant genus distribution in Hunan Province,6 species of the plants distribution in Hunan Province,For the first time to study the structure of Cercis chingii community,and put forword the value of resources protection.The new species and the distribution was found,to some extent,which enriched the floristic data of the flora of hunan.