1. Aulacomnium androgynum (Hedwig) Schwagrichen, Sp. Musc. Frond. Suppl. 3(1,1,Aulacomnion): 2. 1827. (as Aulacomnion).
Bryum androgynum Hedwig, Sp. Musc. Frond., 178. 1801
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.
Organic soil, rotting logs, mineral soil over rock; 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 more or less 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.