Abstract: The aim of our study was to analyze morphological and anatomical characters of the 22 species belonging to the lichen genus Rhizocarpon, found in Xinjiang, China, to provide a morphological basis for the interspecific classification. Twentythree morphological characters of 22 species of Rhizocarpon were coded. Catolechia wahlenbergii and Epilichen scabrosos, belonging to the genus Epilichen and Catolechia in the family Rhizocarponaceae, were designated as outgroup. Their morphological characteristic matrix was analyzed by Maximum Parsimony(MP) method using PAUP, compared with the results of molecular phylogeny based on ITS sequence. After parsimonious analysis, the equally most parsimonious cladograms were obtained, and its strict consensus tree showed that the species of genus Rhizocarpon were divided into two branches according to the type of ascospores, which were composed of species with 1septate ascospores and the species with (sub)muriform ascospores, respectively. R. parvum and R. pusillum, R. geographicum and R. atroflavescens as well as R. macrosporum, R. saurinum and R. furax were gathered in one branch of the phylogenetic trees, respectively.The results of this study were generally consistent with that of molecular phylogenetic analysis. The evolutionary position of some species based on the results of molecular phylogeny was different from that of the phylogenetic trees based on morphological characteristic. From the results of cladistic studies, the type of ascospores was an important taxonomic characters of the genus Rhizocarpon, and the present cladistic study would provide a morphological basis for the evolutionary position of the genus Rhizocarpon.

Key words: Rhizocarpon, morphological characteristics, cladistic, phylogenetic relationships