Systematics Studies Of Radula Dumort. In China

Radula Dumort.,one of the largest genera of Jungermanniopsida,with more than 250 currently accepted species,is classified seven subgenera.The genus is mainly distributed in subtropical and tropical regions,also widely located in China.However,numerous inconsistencies in the genus of China still remain.For the lacking of molecular studies and worldwide taxonomic treatments,the infrageneric and supraspecific classifications are ambiguous,and some complex species have not been solved and the circumscription of many species is debated.In addition,more morphological features are needed to be explored as new evidences for taxonomy of Radula.Therefore,the taxonomic revision of this genus in China is quite necessary.In the present study,a taxonomic revision of Radula in China was carried out depending on molecular phylogenetic and morphological-anatomical analyses.The morphological investigations were mainly based on more than 2000 specimens including 27 type specimens and fresh collections and the herbarium specimens both in China and abroad.For comprehensive molecular phylogenetic analyses,405 accessions belonging to 147 species and seven subgenera were sampled,maximum parsimony(MP),maximum likelihood(ML)and bayesian inference(BI)were performed with combined datasets of four sequences of the chloroplast trnG,trnL-F,rps4 and atpB-rbcL regions.The main results are as follows:1.Based on the present study,37 species of Radula are recognized in China,and the key for subgenera and species is provided.Of them 36 species'morphological features are described in detail,and attached color plates or drawings.Two new species.R.hainanensis L.N.Zhang&R.L.Zhu and R.subacuminata L.N.Zhang&R.L.Zhu.are described and illustrated.Four species,R.mittenii,R.stenocalyx,R.tabularis and R.ventricosa are newly recorded in China.Seven species are excluded from the Radula flora of China:R.amoena,R.aquilegia,R.caduca,R.falcata,R.multiflora,R.parvitexta and R.tjibodensis.Three species,two subspecies and one variety are treated as new synonyms of R.complanata.They are R.complanata subsp.complanata,R.complanata subsp.lindenbergiana,R.lindenbergiana var.atypa,R.acutiloba,R.quadrata and R.tectiloba.Radula stellatogemmipara is treated as a new synonym of R.madagascariensis.2.The present study supports a hierarchical classification of Radula in China with six subgenera,i.e.,subg.Radula,subg.Cladoradula,subg.Odonoradula,subg.Metaradula,subg.Amentuloradula and subg.Volutoradula.Section Epiphyllae Castle ex Grolle is remained,and placed in subg.Metaradula rather than subg.Radula.Section.Epiphyllae Castle emend.R.M.Schust.,sect.Acuminatae,subsect.Stenocalyces and subsect.Acuminatae are synonyms of sect.Epiphyllae Castle ex Grolle.In subg.Cladoradula,sect.Campanigera is remained as a synonym of sect.Cladoradula,and sect.Chinenses is resurrected.Section Retroflexae should be placed in subg.Odontoadula rather than subg.Radula.3.Based on morphological investigations,oil bodies and papillae are newly added and play important roles for taxonomy of subgenera of Radula.Among Radula species in China,oil bodies are divided into three types and papillae are classified into three types.Moreover,these two features also work valuable roles in species and section taxonomy.In conclusion,a taxonomic review of the taxa of Radula in China is better achieved.The results recognize six subgenera of 37 species,confirm classifications of some sections,clear several notorious complexes of close relatives,increase two worthy morphological features,describe two new species and report four newly records,and sequence from forty-seven species are also firstly provided.The results provide valuable information for future studies of Radula,and this study is fairly significant for both protection and utilization of bryophyte resources in the world.