Plants reddish or golden-brown to nearly black; branches frequently with branchlets, some flagelliform, others blunt, especially at the apex of the main shoot and most distal branches. Leaves of stem not strongly overlapping on the red-brown stem, exposing the parallel-oriented abundant filiform paraphyllia, usually 3-lobed, the antical markedly larger than the others, with ciliate margins; branch leaves more closely overlapping; underleaves 2-lobed, margins ciliate. Sexual branches and sporophytes unknown.

Mainly in extremely humid sites in high-moisture climates near the ocean, in peatland, usually somewhat shaded, bogs, cliff shelves, stream banks; 0--50 m, but to 4000 m in Himalayas; B.C. (Queen Charlotte Islands, Pitt Island); Europe (Faeroe Islands, w Ireland, Scotland; Asia (India, Taiwan).

The species is clearly relictual in its whole range, lacking sexual or vegetative reproduction, and the distribution apparently strongly controlled by an extremely high-moisture climate.