Pterygoneurum papillosum Oesau, a distinct moss species, its occurrence in southern England, new to Britain, and the presence of rhizoidal tubers

Pterygoneurum papillosum Oesau (Pottiaceae: Bryophyta) is reported from several widely scattered sites in southern England. These are the first reported occurrences outside Germany, although the species had already been collected at three of the English sites in the 1960s. The species is described and illustrated and its diagnostic characters are discussed. Its status as a distinct species is strongly supported by our observations. Rhizoidal tubers are reported for the first time in this species and in P. ovatum. The habitats of P. papillosum in England are described. It is a winter ephemeral of open calcareous soils that are seasonally moist.