| Subscct.Acerifoliae is a member of Sect.Cheiropsis DC.of Clematis L.of Ranunculaceac.Because the issues of taxonomy and population characteristics of Subsect.Acerifoliae were not clear.DNA Barcode technology was firstly used in taxonomy of Clematis plants in the study to solve the taxonomic status of C.acerifolia var.elobata S.X.Yan,which is endemic to south Taihang Mountain cliff in north Henan province.The taxonomic status of C.acerifolia var.elobata based on morphology has been controversial since its description,so eight molecular markers of two nuclear(ITS and ETS)and six plastid(rps16,rp116,accD,trnS-trnG,atpB-rbcL and trnV-atpE)were used in the DNA Barcoding analysis of Clematis species by author.The results showed that C.acerifolia var.elobata and C.acerifolia var.acerifolia were closely related,but they had differentiated clearly and formed two clades respectively.The mean divergence of the two taxa was 0.78%,which was higher than closely related Clematis species such as C.heracleifolia and C.pinnata(0.50%).Thus considering molecular divergence,morphological differences,and distribution area,the author raised C.acerifolia var.elobata to species level,i.c.Clematis elobata(S.X.Yan)S.X.Yan et L.Xic(stat.&comb.Nov.).Furthermore,the eight selected DNA regions were used to detect the suitability of DNA barcoding in Clematis taxonomy by author.Our results showed that the discrimination power of ITS,ETS,and atpB-rbcL was better than that of the other tested DNA regions.When all tested sequences combined,most of the sampled taxa were resolved.The complete morphology description and comparison of Subsect.Acerijoliae and its members were conducted in the study base on a great deal of field population survey,observation and and statistics of 74 specimens stored in several specimen museum(i.e.,PE and etc.),in order to provide the exact evidence for the taxonomic status of C.acerifolia var.elohata,which being upgraded to the level of species level.Meanwhile,a specimen of C.elobata(S.S.Kuang 261,HENC)stored in the Museum of the Henan Normal University was discovered to be an isotypc of C.elobata.Achcnc's germination characteristics and seedling morphology of Subsect.Acerifoliae members were firstly observed,described and compared in the research,and were compared them with other plants of Clematis.Achenes of 14 Clematis taxa were used as the research materials in this study and 10 species among them were reported for the first time,i.e.Clematis acerifolia,C.elobata,C.armandii,C.brevicaudata,C.peterae,C.repens,C.tomentella,C.uncinata,C.urophylla and C.pilulifera.The results showed that 7 species and 1 variety had alternate leaves on their seedlings,including C.acerifolia,C.elobata,C.aethusifolia,C.brevicaudata,C.peterae,C.macropetala,C.repens,and C.urophylla.Among them,C.macropetala and C.aethusifolia appeared to have hypogeal seedlings,whereas the other species had epigeal seedlings.Seedlings morphology of C.acerifolia and C.elobata were completely consistent to those of C.peterae,C.repens,C.brevicaudata and C.urophylla,but were basically consistent to those of C.macropetala and C.aethusifolia,the differences are that the former have elongate hypocotyls and the later have condensed hypocotyls.The distribution area,habitat,elevation,community companion species,number of individuals,endemic and endangered degree and so on of Subsect.Acerifoliae plants were preliminarily comfirmed in the study.The results showed that ten distribution sites were confirmed new distribution sites of C.elobata.Tthe distribution center of C.acerifolia was Beijing(North Taihang Mountain),but the distribution center of C.elobata was Xiuwu County and Hui County of Henan province(North Taihang Mountain).The straight-line distance of the two distribution centers is about 580 km.Subsect.Acerifoliae plants were the earliest flowering species of Clematis plants in North China and the florescence of C.acerifolia is shorter than C.elobata.The distribution elevation of C.acerifolia was 100-600 m,C.elobata was 600-1300 m.The habitat of Subsect.cerifoliae plants were on the precipitous rock faces and sheer cliffs,or in the shrub of steep slopes.The common companion plants of Subsect.Acerifoliae Plants were Oresitrophe rupifraga Bunge,Corydalis fangshanensis W.T.Wang ex S.Y.He,Myripnois dioica Bunge and Viola dissecta Ledeb.and so on.A great deal of detailed and in-depth studies on the section were carried out in the study,which including taxonomic status and relationship,germination characteristics and morphological characteristics of seedling,phenology,geographical distribution,habitat,community structure,companion plant,individua quantity,endemicity,endangered degree and so on,in order to provides a reliable theoretical basis for the protection and development and utilization of Subsect.Acerifoliae plants. |
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