| Chengbu County belongs to Shaoyang City,Hunan Province.It has high mountains,crisscross rivers,high in the south and low in the north.Its plant species diversity is extremely rich.Through a large number of field investigations,specimen identification,and related literature statistics,this study has basically found out the species status of seed plants in Chengbu County.At the same time,the species diversity of seed plants in the county was analyzed from the perspectives of seed plant species,rare plants and alien invasive plant resources.The main results are as follows:(1)The diversity of seed plants in Chengbu County is rich,and the floristic geographical composition is complex.There are 2183 species of seed plants belonging to 846 genera and 185 families in Chengbu County.Among them,gymnosperms have 9 families,17 genera and 26 species;There are 176 families,829 genera and 2157 species of angiosperms.In addition to cultivated and exotic plants,there are 2042 species of native wild seed plants of 174 families,776 genera in Chengbu County.(2)The 174 families in Chengbu County can be divided into 11 distribution types,including 79 families in the tropics and 44 families in the temperate zone,accounting for 45.40%and 25.29%of the total families respectively.From the level of families,the flora in Chengbu County has obvious tropical characteristics.776 genera can be divided into 14 distribution types and 18 distribution forms.The ratio of genera of tropical elements to those of temperate elements is about 1:1.02,which is roughly equal.(3)The endemic phenomenon of Chengbu County is relatively obvious.Although there are no strictly Chinese endemic families,there are 2 quasi-Chinese families,namely Bretschneideraceae and Sargentodoxaceae;There are 3 families endemic to East Asia,namely Cephalotaxaceae,Actinidiaceae and Stachyuraceae;31 genera are endemic to China,accounting for 12.97%of the endemic genera of seed plants in China,of which South China,Central China and East China constitute the majority;There are 817 species endemic to China,belonging to 126 families and 353 genera.The rich endemic resources reflect the nature of the intersection of multiple floristic elements in the flora of Chengbu County.In the flora,it is located at the intersection of the four major flora of China,namely,Central China,South China,East China and Southwest.(4)At present,a total of 71 species of protected plants have been sorted out and found in Chengbu County,including 43 species of national key protected wild plants(4 species of national primary protection and 39 species of national secondary protection),and 28 species of local key protected plants in Hunan Province.At the same time,the orchid plant resources in the county are also extremely rich,with a total of 63 species belonging to 31 genera.At the same time,based on the current situation of field investigations,we analyzes the risk factors of rare and endangered plants in Chengbu County,puts forward relevant protection suggestions.(5)At present,38 species of alien invasive plants belonging to 16 families and 33 genera have been found in Chengbu County.Among them,native North America has the highest frequency of 21,accounting for 38.23%of the total number of alien invasive plants.The second is South America,with 17 times,accounting for 30.91%of the total number of alien invasive plants.Among the alien invasive plants,there are 34 species of herbs,accounting for 89.47%of the total.The degree of invasion of alien invasive plants in Chengbu County was evaluated,and the correlation between their origin and life forms was analyzed.The control strategies for alien invasive plants were proposed.(6)According to the field survey and literature data in Chengbu County,a new plant species was found,which is proposed to be Oreocharis caotierui X.L.Yu,L.Wu&A.liu,and is now in the submission stage.There are 5 species newly recorded in Hunan Province,including 2 new recorded genera,one doubtful species of Smilax. |
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