Aulacomnium Schwägr.

Elements in the following description are taken from Crum (1994).

Plants small to robust, erect, growing on soil and rotten wood. Stems erect, simple or sparsely branched (and reportedly branching by innovation), tomentose, in cross-section with a strong central strand. Leaves erect to erect-spreading, crowded, often somewhat larger near stem apex, contorted when dry in N.Z. species, oblong-lanceolate to elliptic, acute to broadly rounded at apex, concave or keeled above, mostly revolute at margins; laminal cells mostly short or ± isodiametric, incrassate and sometimes collenchymatous, strongly singly papillose-mammillate on both surfaces (in N.Z. species) or smooth; basal cells sometimes swollen and coloured; alar cells not differentiated. Costa stout, usually sinuose above, failing below the apex, often lustrous and projecting abaxially in dry material, in cross-section with two stereid bands. Gemmae sometimes present on pseudopodia at stem apices.

Dioicous (in N.Z. species) or rarely autoicous. Setae terminal, elongate, erect, smooth; capsules suberect to inclined to horizontal, symmetric or curved, oblong-ovoid to cylindric, short-necked, furrowed; exothecial cells firm-walled; stomata superficial; annulus well developed and revoluble; operculum conic to short-rostrate. Peristome double, bryoid. Calyptra cucullate, smooth, and naked. Spores spherical.

A genus of five to six species occurring on soil or rotten wood. The genus is widely distributed in the northern hemisphere. Only one species, A. palustre, occurs in the southern hemisphere, where it is probably adventive.