Plants small to medium-sized, gregarious or loosely tufted, light green to hyaline with faint reddish tint; terricolous. Stems 4-10 mm high, julaceous, infrequently branched, sparsely radiculose below; in section rounded, inner cortical cells in 2-3 rows, thin-walled, hyaline, outer cortical cells in 2 rows, weakly thickened, reddish. Leaves imbricate wet or dry, concave; broadly ovate, 0.6-1.0 mm long, 0.5-0.7 mm wide; apex acute, hyaline; margins plane to erect, entire. Costa reddish, ending below apex to subpercurrent; in section bulging dorsally, ventral cells 2-3, in single layer, large, thin-walled, dorsal stereid band 3-4 cells thick, occasionally cells only weakly thickened, dorsal surface cells 3-4, slightly smaller then ventral cells. Upper laminal cells rhomboidal to oblong-rhomboidal, 2-4: 1, hyaline, lax, thin-walled but firmer below; upper marginal cells short-rectangular, in 1-2 rows, not forming distinct border; basal cells rectangular, 2-3: 1, thin-walled, reddish. Dioicous. Male plants similar, perigonia terminal or lateral through innovation. Perichaetia terminal, frequently overgrown by subperichaetial innovations; leaves triangular to elliptical, 1.2-1.5 mm long, reddish to yellowish. Seta 6-10 mm long, stout, ±curved, yellow-brown; capsules horizontal to pendulous, clavate or gibbous, to 5 mm long, mouth oblique, neck differentiated, 1-2 mm long; exothecial cells irregularly rectangular, thickened, smaller and quadrate at mouth; stomata cryptopore, numerous on neck; annulus differentiated; peristome double, exostome teeth triangular, 0.3 mm long, weakly papillose, shorter than endostome, endostome segments narrow above high basal membrane, yellowish, weakly papillose, cilia rudimentary; operculum conical; spores large, rounded, 30-40 µm, yellow-brown, papillose.
On soil of cliff faces or rock crevices in the grass-heathlands of Lesotho and the Drakensberg escarpment of Natal and at high altitudes in Natal.
New to southern Africa, P. zierii is also known from Europe, Asia, India, northern Africa and North America. In the Flora area the species is found in Lesotho and the Drakensberg escarpment of Natal and at high altitudes in Natal.