Dioicous or rarely autoicous. Plants small to rather robust in dull green, yellow-green or yellowish brown radiculose tufts, usually tomentose. Stems erect, simple or branched, sometimes terminating in filiform pseudopodia bearing minute leaf-like ecostate gemmae in an apical cluster. Leaves variable, crowded, erect to spreading, unchanged or contorted when dry, lanceolate to oblong-ovate, concave or keeled; margin entire or serrate above, ±revolute, unbordered; costa strong with 2 stereid bands, tapered and flexuose above, ending below apex; upper laminal cells small, isodiametric to elliptical, incrassate, smooth or papillose.

Calyptra cucullate, smooth. Setae terminal, ±elongate, erect. Capsules erect to horizontal, symmetrical to asymmetrical, oblong-ovoid to cylindrical, plicate when dry, with 8 longitudinal ribs; apophysis short; annulus broad; operculum bluntly conical to obliquely rostrate; stomata only on apophysis. Peristome double; exostome teeth lanceolate, papillose with numerous lamellae; endostome with a tall basal membrane, keeled, the processes usually perforate; cilia long, slender, nodulose, in groups of 2–4. Spores small.

Aulacomniaceae Schimp., Syn. Musc. Eur. 411 (1860). Type: Aulacomnium Schwägr.

As defined here, the family is monogeneric, and Leptotheca Schwägr., formerly included in this family, is treated under the Rhizogoniaceae. According to the classification of Goffinet et al. (2012), the Aulacomniaceae also includes Hymenodontopsis Herzog and Mesochaete Lindb. However, both are referred to the Rhizogoniaceae here, the former being a recent addition to the Australian bryoflora for Pyrrhobryum bifarium.

Crum, H.A. (1994), Aulacomniaceae, Moss Flora of Mexico 2: 535–537.

Goffinet, B., Buck, W.R. & Shaw, A.J. (2012), Classification of the Bryophyta. http://www.eeb.uconn.edu/people/goffinet/Classificationmosses.html

Seppelt, R.D. (2004), The Moss Flora of Macquarie Island. Australian Antarctic Division, Kingston.

Smith, A.J.E. (1978), Aulacomniaceae, Moss Flora of Britain and Ireland 447–451.

G.H.Bell & D.G.Catcheside (2012), Australian Mosses Online 45. Aulacomniaceae. Australian Biological Resources Study, Canberra. Version 16 June 2012. http://www.anbg.gov.au/abrs/Mosses_online/45_Aulacomniaceae.html

First published as: G.H.Bell & D.G.Catcheside (2006), Aulacomniaceae, Flora of Australia Volume 51: 245–247. Australian Biological Resources Study, Canberra & CSIRO Publishing, Melbourne.