| The Luzhijiang valley is located in the core of the central plateau of Yunnan Province.The valley is deep,the geological history is long and the natural climate is special.There are typical sparse shrub of dry-hot valley and monsoon forest vegetation in the area.And the plant species diversity is very rich,the unique phenomenon is remarkable,but the previous plant investigation and research for this area are relatively weak.Based on field investigation,specimen collection,specimen identification and data collection,we compiled a list of wild seed plants of Luzhijiang valley,and analyzed the area of vegetation and the composition of seed plant flora,the results showed that:(1)The study was carried out 12 field surveys in different seasons,and 1137 specimens were collected.Through the systematic finishing and identification,we recorded that the Luzhijiang valley had a total of 965 kinds of wild seed plants,which are subordinate to 154 families,584 genera(according to Hutchinson system).Among these taxa,3 families,4 genera,6 species are gymnosperms;the other 151 families,580 genera,959 species are angiosperms.The result showed it was one of the most abundant seed plants in central Yunnan.(2)The seed plant's flora of Luzhijiang valley is basically subtropical in nature,obvious in adapting to the xerophytic environment.The 151 families of angiosperm are divided into 9 types and 9 subtypes,581 genera are divided into 15 types and 22 subtypes.Among them,there are 74 families and 337 genera of tropical plants,accounting for 49.01%and 58.10%of the total number of angiosperms and the total genera.(3)The Luzhijiang valley has wide origins and connection in geographical relationships,a number of floristic sources are integrated here.From the analysis of existing floristic pattern,the flora of Luzhijiang valley is the most close to that of Jinsha River and Yuanjiang valley.So we can speculate the region may be a middle-ground between the both rivers.(4)The unique phenomenon is obvious in Luzhijiang valley,at the same time,ancient endemism and new endemism coexist.Which indicates the origin of the flora is ancient,the area is a shelter for ancient relict species.On the other hand,the habitat of this area is by specialization,It is a important area of some new species formation and differentiation.(5)The Luzhijiang valley is dry-hot valley,relatively closed environment make this area form and retain a large number of rare and endangered plants and endemic species,which has important significance of phytogeography.For the first time,we found the plants:Spodiopogon sagittifolius and Paradombeya sinensis,which both belong to the second ranking in our country's protection category.The new discovery of Terminalia myriocarpa in Xiaoluzhi,Yimen,which also falls into the second-ranking protection category,is the most northern record of the Yunnan Plateau.Trailliaedoxa gracilis which is the plant of Chinese endemic genera,was found a large area of the distribution of records in the area.Moreover,we also found a suspected new species Pterygiella luzhijiangensis and a new record of Yunnan Geodorum eulophioides.In short,special habitat in the region.The seed plant's flora has characteristics of rich species,strong endemism,numerous survivors,ancient origin.So the region is an important area for the formation of new species differentiation,which is an important channel for the migration of north and south plants. |
PDF Full Text Request