Re-evaluation of Hymenostylium xanthocarpum (Hook.) Brid., and Ardeuma RHZander & Hedd., a new name for all other species of Hymenostylium (Pottiaceae, Bryophyta)

摘要

The Old World Hymenostylium xanthocarpum, the generitype of Hymenostylium, was found to be unrelated to the widespread H. recurvirostrum and other species currently placed in the genus. Major distinguishing traits of H. xanthocarpum are the presence of a stem central strand, leaves broadest about midleaf and constricted just above the base, distal laminal cells usually ventrally bulging and massively unipapillose, and basal cells differentiated only in the lower 1/5-1/7 of the leaf. A new genus name, Ardeuma, is proposed for the remaining species of Hymenostylium, and combinations are made for those that are commonly recognized. A key to Tuerckheimia species in the New World that may be confused with H. xanthocarpum is provided.