Anoectangium Schwägr.

The following generic description is modified from Zander 1993.

Plants green to yellow-brown above, brown below, forming turves or mats on soil or rock. Stems simple or branched, in cross-section with central strand present, sclerodermis weakly to well developed (in N.Z. species), and hyalodermis absent. Leaves erect-spreading (in N.Z. species) to spreading when moist, erect, incurved and often individually twisted when dry, linear to lanceolate (in N.Z. species) or triangular, with apex obtuse, acute or acuminate (in N.Z. species); margins plane or weakly recurved below (in N.Z. species); upper laminal cells clear in outline to obscure (in N.Z. species), usually subquadrate, thin- to very thick-walled and densely papillose; upper marginal cells not differentiated; lower laminal cells differentiated only in extreme leaf base. Costa failing, or percurrent to shortly excurrent (in N.Z. species), in cross-section with 1 stereid band. Laminal KOH colour reaction yellow to yellow-orange.

Dioicous. Perichaetia terminal on short lateral branches. Perigonia lateral. Setae elongate. Capsules ovoid to broad-cylindric, with tapered neck. Operculum long-rostrate. Peristome lacking. Spores 9–12(–19) µm, variably papillose.

Anoectangium has historically (Brotherus 1924; Sainsbury 1955) and more recently (Saito 1975; Zander 1977​​​​​​​) been placed in subfamily Pleuroweisioideae or in tribe Pleuroweisieae of subfamily Pottioideae, with key features being the lateral perichaetia and lack of peristome. Zander later (1993​​​​​​​, p. 136) emphasised the shape of the dorsal stereid band as seen in costal cross-section, and placed the genus in the tribe Barbuleae, in subfamily Merceyoideae (now Barbuloideae).

A genus of some 50 species, widely distributed in many climatic regions. The single N.Z. species recognised here is widespread in both temperate and tropical regions of the world.