Picobryum, a new genus of Pottiaceae (Bryophyta) from South Africa, and an erratum for Acaulonopsis.

A new genus, Picobryum (Pottiaceae, Bryophyta), including one new species, Picobryum atomicum, is described from the western Cape Province of South Africa. The new taxon is somewhat similar to Syntrichia gametophytically but differs in the trait combination: stem very short, central strand absent; leaves strongly reflexed to squarrose when moist, usually folded longitudinally on one side, bases sheathing, margins plane throughout, irregularly and weakly bordered in 1(–2) rows with somewhat thick-walled, less papillose cells; papillae large, simple to bifid, 1–2 per lumen; paroicous; seta essentially absent; capsule cleistocarpic, globose, and short-apiculate; calyptra mitrate. Locality data for the type of Acaulonopsis fynbosensis R.H.Zander & Hedd. are corrected in an erratum