1. Pylaisiadelpha tenuirostris (Bruch & Schimper ex Sullivant) W. R. Buck, Yushania. 1(2): 13. 1984.
Leskea tenuirostris Bruch & Schimper ex Sullivant in A. Gray, Manual, 668. 1848; Brotherella tenuirostris (Bruch & Schimper ex Sullivant) M. Fleischer
Stems red-brown, reclining,r, branches prostrate or sometimes arching upward; pseudoparaphyllia narrow, foliose. Stem leaves crowded, 0.7-1 mm. Branch leaves similar, slightly smaller. Specialized asexual reproduction by filiform propagula in leaf axils. Seta reddish. Capsule symmetric, 1 mm.
Capsules mature early spring. Rock, epiphytic on tree trunks and bases, logs, broadleaf woodlands; low to moderate elevations; Nfld. and Labr., N.S., Ont.; Ala., Ark., Conn., Ga., Ill., Ind., Maine, Md., Mich., Mo., N.Y., N.C., Ohio, Okla., S.C., Tenn., Vt., Va., W. Va., Wis.; Mexico; Central America; Asia.
Pylaisiadelpha tenuirostris is superficially similar to some specimens of Hypnum pallescens (Hypnaceae), a commonly sporophyte-bearing species with conic opercula and leaves lacking enlarged alar cells. Plants with sporophytes are rare. The rostrate opercula and conspicuous pigmented enlarged alar cells are distinctive.