Flora Of Seed Plants In Zhuguang Mountains

Since biodiversity is having a sharp decline nowadays,the protection of plants diversity draws a lot attention.And the protection of plants biodiversity is supported by basic data like flora studies.The flora of South China and East China is a core part of China-Japan flora.Luoxiao Mountains is one of most important parts in Southeastern China.Zhuguang Mountains is the southern part of the Luoxiao Moutains along the border of Hunan and Jiangxi province,running from northeast to southwest.Thus,the studies of Zhuguang Mountains flora will enrich the knowledges of Luoxiao Mountains flora.Basing on 8800 specimens collected and identified during field investigation from May 2013 to October 2017,and a compiled data from Chinese Virtual Herbarium(CVH)and collected literatures,all known seed plants species in Zhuguang Mountains was listed.Then the species,composition and endemism of flora in Zhuguang Mountains were studied using cluster analysis with nearby regions to reveal its origin.Results are as follows:1.The floristic compositions of seed plant flora in Zhuguang Mountains are abundant.A total of 2442 species(including subspecies and variants,the same bellow)of seed plants belonging to 915 genera and 192 families distributed in Zhuguang Mountains.Among them,there are 29 gymnosperm species from 23 genera and 9 families.The families,genera,and species of Zhuguang Mountains seed plants flora consist 91.00%,63.23%,and 49.51%of seed plants families,genera,and species of Hunan Province respectively,and form 96.00%,78.88%,and 49.51%of seed plants families,genera,and species from Jiangxi Province.Furthermore,it makes up 55.81%,28.74%,and 8.51%of Chinese flora families,genera,and species.Thus,the abundant seed plant flora in Zhuguang Mountains plays a vital role in Hunan and Jiangxi Province,and even in entire southeastern Chinese flora.Analysis of plant families,genera and species shows that:Typical families of flora are:Fagaceae,Lauraceae,Theaceae,Ericaceae,and Aquifoliaceae,etc.,are dominant families of the flora of Zhuguang Mountains,which also,have important biological,and phytogeographical implications.And typical genera of flora mainly are:Symplocos,Ilex,Rhododendron,Eurya,Viburnum,Lithocarpus,Ficus,Camellia,Litsea,Machilus,Cinnamomum,Linder a,Neolitsea,Quercus,Magnolia,Michelia,and Phyllostachys,etc.Dominant families and genera contribute to the flora of Zhuguang Mountains most,less than 15%of large families holds about 50%of genera and species.The families from IV and V class are many,but hold few genera and species.This indicates that the flora of Zhuguang Moutains is diversify and complex,and also,the area is where many families and genera meets and interpenetrate.High proportion of families with one or few species indicates that the seed plants flora here has its own ways of phylogeny and evolution.2.The flora of Zhuguang Mountains are characteristic by elements of tropical northern edge.The floral geographical elements of Zhuguang Mountains are complex.There are 12 distribution types and 13 sub-distribution types for families,14 distribution-type and 30 sub-distribution types for families.There are 87 tropical families in Zhuguang Mountains occupying 65.91%of the non-worldwide distributed families of the Mountains;and 44 temperate families accounts for 33.33%of the non-worldwide distributed families of the Mountains.Tropical families whose distribute center located in eastern Asia are dominant element,its proportion much higher than the temperate families.This suggests the flora here is strongly connected with tropic flora.The distribution types of genera indicate that the flora here is affected in geological history by plants flora from different region.And the different proportion of elements from different region shows the degree of intimacy.Among them,the largest distribution type is Tropical Asian,which holds 240 genera,accounts for 30.86%non-worldwide distributed genera.The second large distribution type is Pantropic which has 155 genera and occupying 19.92%of total non-worldwide genera.The north Temperate has 130 genera,makes 16.71%of total non-worldwide genera.A total of 395 tropical genera are distributed in Zhuguang Mountains,occupying 50.78%of total of the non-worldwide distributed genera,this makes them dominant component of genera.There are 383 temperate genera,account for 49.23%of non-worldwide distributed genera.R/T value is 1.03,the proportion of tropical and temperate species is basically equal with eastern China seed plants flora(50.63%).This indicate that the flora of Zhuguang Mountains is closely related with flora of eastern China.On the other hand,the flora here has many elements from flora of southern China,like Apostasia,Homalium,Ixonanthes,Passiflora,etc.,this shows the flora of Zhuguang Mountains are closely related with flora of southern China,which located in northern tropic.3.The endemism of the flora of Zhuguang Mountains is prominent.There are 3 families endemic to East Asia and 2 families,32 genera,and 919 species endemic to China distributed in the Zhuguang Mountains There are 18 Chinese endemic single species genera,which make 59.26%of all Chinese endemic genera distributed in the Mountains.The majority of these genera are woody,and primitive and ancient in phylogenetic evolution.Such as Ginkgo,Cathaya,Cyclocarya,Bretschneidera,Semiliquidambar,and Eucommiaet,etc.This shows that the seed plants flora of Zhuguang are ancient and relic.3.The flora of Zhuguang Mountians origined anciently.The flora of Zhuguang Mountians is multiply affected by southern,south-central,and southeastern Chinese flora.Components of temperate and tropic are comparative,and the transition characteristics are prominent.Cathay argvrophylla,Tsuga chinensis,Amentotaxus argotaenia,Taxus wallichiana var.Mairei and Cephalotaxus sinensis are originated or distributed majorly in South China.At the same time,tropical species like Gnetum parvifolium,Artocarpus hypargyreus,Altingia chinensis,Pentaphylax euryoides,Apostasia ramifera and Phyllagathis guidongensis also distributed here.Basing on analyze of data acquired,the origin of the flora here is not late than Tertiary.According to modern distribution of the flora,it is assumed that the flora here may have 3 dispersal routes.Multiple elements met and coexist,compete and adapt during long term environmental adaption and evolution,form the modern flora of Zhuguang Mountains.4.The flora of Zhuguang Mountians origined a long time ago.The flora of Zhuguang Mountians is multiply affected by southern,south-central,and southeastern Chinese flora.Components of temperate and tropic are comparative,and the transition characteristics are prominent.Cathay argvrophylla,Tsuga chinensis,Amentotaxus argotaenia,Taxus wallichiana var.Mairei and Cephalotaxus sinensis are originated or distributed majorly in South China.At the same time,tropical species like Gnetum parvifolium,Artocarpus hypargyreus,Altingia chinensis,Pentaphylax euryoides,Apostasia ramifera and Phyllagathis guidongensis also distributed here.Basing on analyze of data acquired,the origin of the flora here is not late than Tertiary.According to modern distribution of the flora,it is assumed that the flora here may have 3 dispersal routes.Multiple elements met and coexist,compete and adapt during long term environmental adaption and evolution,form the modern flora of Zhuguang Mountains.5.New discovery of the seed plant flora of Zhuguang Mountains.A total of 3 new species belongs to Melastomataceae and Gesneriaceae were described,namely Phyllagathis guidongensis K.M.Liu&J.Tian,Primulina hengshanensis L.H.Liu&K.M.Liu.and Primulina longiloba L.Zhou&J.Tian sp.nov.Six new species record to Hunan Procvince are Lindera acutivena Hay.,Lysimachia fordiana Oliv.,Merremia quinata(R.Br.)V.Ooststr.,Melampyrum laxum Miq.,Oreocharis curvituba J.J.Wei&W.B.Xu,Oreocharis magnidens Chun ex K.Y.Pan.And 5 newly found population of endangered species,Semiliquidambar cathayensis H.T.Chang,Coptis chinensis Franch.,Panax japonicus C.A.Mey.,Brasenia schreberi J.F.Gmel.,and Caldesia grandis Sam.