Fissidens hyalinus is often considered to be one of the rarest mosses in the eastern United States. The species, however, is much more abundant than has previously been assumed. Sixty-five new collections of F. hyalinus, in combination with previous collections, document the species from 28 counties, 7 states, and 5 major physiographic provinces. The species is most abundant on bare soil of streambanks in steep and deeply dissected landscapes with calcareous geology and mixed deciduous forests.

Key words: Fissidens hyalinus, Fissidentaceae, moss