Notoligotrichum synonymised with Atrichopsis (Polytrichaceae, Bryophyta), with two new species from South Africa

Recent phylogenetic analyses of the moss family Polytrichaceae have identified a clade of generally small-sized species exclusively distributed in southern temperate regions and the New World tropics. This group is sister to all other species in the family that have the characteristic polytrichaceous toothed peristome and epiphragm structure, with most members having been previously placed in superficially similar, predominantly Northern Hemisphere genera. The South African members of this group have been poorly understood, and are here treated taxonomically in the context of a new phylogenetic analysis of Itatiella, Notoligotrichum, Oligotrichum and Psilopilum with increased sampling from South Africa. Additionally, new combinations are made to accommodate all members of the Notoligotrichum clade under Atrichopsis. The South African species occur as two clades in Atrichopsis that diverge prior to the origin of a large Australasian and South American clade. One comprises Atrichopsis wageri comb. nov. (≡ Oligotrichum wageri) and the other A. tetragona sp. nov. and A. capensis sp. nov., two species previously described under Oligotrichum but not effectively published. We formally describe and illustrate the three South African species of Atrichopsis and provide an identification key, illustrations, and distribution maps for these species.