Sp. Musc. Frond. Suppl. 3(1,1,Aulacomnion): 2. 1827.
Plants 1–2 cm, in erect, basal tufts or cushions, green or brownish green. Stems yellow or brownish green; cross section irregularly pentagonal, cortical cells in 2–4 layers, medulla cell walls thick or thin, central strand cells small; rhizoids between leaves near base of plants. Leaves distant near base of plants, more congested toward apex, not much different when dry or moist, oblong-lanceolate, widest above base, somewhat concave to keeled; base slightly rounded to insertion; margins revolute to mid leaf, weakly serrulate proximally, irregularly serrulate toward apex; apex acute; costa flexuose; laminal cells round or nearly oblong, papillae blunt; basal cells 1-stratose, hyaline. Specialized asexual reproduction by small fusiform propagula in tight globose cluster. Perigonia budlike in series down stem; paraphyses of 7–10 cells. Perichaetia with paraphyses of 9–12 cells. Seta 1–1.5 cm. Capsule suberect or horizontal, 2.5–3 mm; operculum conic, rostrum short, blunt; endostome cilia nodose. Spores 10–20 µm, smooth.
Habitat: Organic soil, rotting logs, mineral soil over rock
Elevation: low to moderate elevations
B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Alaska, Calif., Colo., Idaho, Ill., Maine, Mich., Mont., N.H., N.Y., Oreg., S.Dak., Wash., W.Va., Wyo.
The propagula of Aulacomnium androgynum, borne in spheric clusters at the ends of naked branches, are a distinguishing feature. This is the only species of Aulacomnium with small lanceolate leaves that are serrulate mainly beyond mid leaf and shortly rounded at the insertion. The species also lacks a hyalodermis. The distal laminal cells of A. androgynum are round or ± oblong, 1-papillose on abaxial and adaxial walls, with blunt, long papillae and thick walls. The basal laminal cells of the inner perigonial leaves are elongate to rhomboidal, large, and smooth.