New insights into the genus Stoneobryum (Bryophyta: Orthotrichaceae) based on recent collections of the two known species

The morphological traits of the two known species of the genus Stoneobryum are reexamined based on newly collected materials. Observations on the Australian species, S. bunyaense, are derived from a recent collection made at the type locality, where it has been rediscovered. Those of S. mirum are based on recent field collections from numerous locations in eastern South Africa. Comprehensive descriptions of both species and illustrations of their key morphological characters are provided. The new data complement and correct previously available descriptions, especially the original one for the type species of the genus, S. bunyaense. Stoneobryum arises as a highly differentiated genus, well characterized by sporophytic and gametophytic characters. Its two species are very similar, but nevertheless certainly distinct; an identification key is provided.