Leaves gradually contracted into a long, fine point that is hyaline at the extreme apex.

Wet rocks, damp cliffs, seepage banks, bogs or wet humic soil, always in open habitats at sea level along the coast, or at about 1500 m in the Appalachian Mountains; 0--1500 m; Alaska, B.C. Wash., Nfld., N.C.; Europe; Asia.

The population in the Appalachian Mountains differs by greenish, not blackish plants, smaller size, less developed alar cells and less incrassate, basal laminal cell walls. Such plants have been described from similar habitats and similar elevations from the Alps of Europe as C. adustus De Notaris. It is not known whether these populations in non-coastal areas are genotypically different or just modifications associated with higher elevations. It may perhaps deserve to be recognized at the varietal rank. Forms with falcate leaves as occurring in Europe or Asia have not yet been found in North America. Sporophytes, produced very rarely, were found in North America only once, in B.C.