Taxonomic notes on Sorbusmegalocarpa (Rosaceae) and related taxa

Four Sorbus taxa endemic to China, S.arguta, S.guanxianensis, S.megalocarpavar.megalocarpa and S.megalocarpavar.cuneata, are morphologically similar to one another in having large brown fruits with persistent calyx and dense lenticels. In literature, either all of the four taxa were accepted, or two of them, S.arguta and S.megalocarpavar.cuneata, were treated as synonyms of S.megalocarpavar.megalocarpa, or S.guanxianensis alone was dubious. In this study, based on morphological comparison, S.arguta is reinstated for its relatively small inflorescence, small fruit and timing of flowering after leaves are unfolded. S.megalocarpavar.cuneata is confirmed as a synonym and S.guanxianensis is proposed as a new heterotypic synonym of S.megalocarpa.