Taxonomical Research On The Simple-leaf Taxa Of Sorbus Based On The Statistical Method And Morphological Characters

Sorbus belongs to the Maloideae of Rosaceae,distributing around the temperate zone of northern hemisphere.The origin distributioncenters are the Caucasus region along the Black Sea and the south-western region of China.There are more than 100 species of Sorbus in the world,more than 60 species in China and some of which are endemic.China is one of the most abundant countries in the world known for its ecological resources.Excessive types of morphological traits in the species of Sorbus and the existence of crosshybrid fusion phenomena have led to debate among species.Whether Sorbus should be included single-leaf group or compound-leaf group,and how the single-leaf group can form a independent genus is still questionable.The results of different scholars are not identical.Although the technical methods such as molecular systematics and quantitative taxonomy have made great progress,but the basic taxonomic research on the taxa of leaf is rarely.In this paper,32 species of Sorbus were collected from Yunnan,Sichuan,Xizang,Zhejiang,Shandong and other areas by the method of investigate and count.According to the similarity and variability for the characteristics of vane,42 characters with apparent taxonomic significance were selected and their genetic characteristics were discussed.At the same time,the information of geographical were discussed according to the records of samples.The thesis concluded that the distributed pattern of Sorbus can be divided into four models,they are Yun-Gui-Chuan distribution,Himalaya distribution,Qinling-Tai hangdistribution,Central-China distribution.Comprehensively considerated about nume rical taxonomy,distribution and previous achievements of molecular phylogeny and p-hylogeography study,then amend a new taxonomy system in this paper:I.Sect.Aria Pers.(a)Ser.Megalocarpae Yü.Retained the status of classification.(b)Ser.Thibeticae Yü.Retained the status of classification and separated S.xanthoneura from S.hemsleyi(Schneid.)Rehd.Restored the taxonomic status of S.xant-honeura Rehd.II.Sect.Micromeles(Dcne.)Rehd.(c)Ser.Folgnerianae Yü.S.granulosa in Ser.Thomsonianae Yü are transferredto Ser.Folgnerianae Yü.S.folgneri(Schneid.)Rehd.and S.tsinlingensis C.L.T ang were treated to be one species and the last name was the synonyms of S.folg n-eri Rehd.(d)Ser.Ferrugineae Yü.S.aronioides Rehd.S.keissleri(Schneid.)Rehd.and S.thomsonii(King)Rehd.in Ser.Thomsonianae Yü were transferred to this system.(e)Ser.Alnifoliae Yü.S.globosa T.T.Yu & H.T.Tsai and S.rhombifolia C.J.Qi & K.W.Liu in Ser.Thomsonianae Yü and Ser.Alnifoliae Yü are transferred to Ser.Alnifoliae Yü.Due to the section containing the typical species of Ser.Alnifoliae Yü so keep the name of Ser.Alnifoliae Yü.Besides,the species of Sorbus native to China were revsied.The status of classification of Pleiosorbus megacarpu L.H.Zhou et C.Y.Wu was resumed and the name of Sorbus megacarpus(L.H.Zhou et C.Y.Wu)L.D.Lu was not applied tentativly.S.tsinlingensis C.L.Tang was comfirming to be the synonym of S.folgneri(Schneid.)Rehd.