Pleurophascum Lindb.

Plants yellow- or brown-green, ± comose, sometimes hoary, forming loose turves or cushions. Primary stems creeping and subterranean, with minute, scale-like leaves. Secondary stems erect, branching laterally or by innovation, usually julaceous, in cross-section with a small central strand and weakly differentiated cortical cells. Leaves crowded at stem apices, broadly elliptic to nearly cochleariform, variably shaped at apices, concave, appressed or erect-spreading, decurrent or not, not bordered; margins erect or narrowly recurved, entire or toothed; mid laminal cells oblong or oblong-hexagonal, very thick-walled and highly porose; basal cells elongate and porose; alar cells weakly differentiated, usually shorter and wider than adjacent laminal cells. Costa absent.

Dioicous. Perichaetia on short lateral branches arising from the secondary stems (in N.Z. species), or terminating secondary stems, mostly enlarging after fertilisation. Perigonia gemmiform, scattered, lateral on secondary stems (in N.Z. species) or terminal. Setae erect, smooth, elongate (in N.Z. species) or very short; capsules very large, discoid, globose, or obovoid, inoperculate, bluntly rostrate or rounded at apex; spore sac ± globose, attached to the exothecial wall by anastomosing cellular filaments; columella present; stomata present or absent at capsule base. Calyptra cucullate, ± split at base, dark brown, enclosing only the apical rostrum at capsule maturity, often enclosing a second hyaline membrane (like an internal mitrate calyptra). Spores large, smooth.

A genus of three Australasian species, all with restricted distributions. The two species occurring outside N.Z. are a Tasmanian endemic (P. grandiglobum) and a Western Australian endemic (P. occidentale).

Its unique morphology has made this genus famous in the annals of Australasian botany; Lindberg (1875) considered Pleurophascum to be "of no less interest to the Muscologist than is Rafflesia or Welwitschia to the Phanerogamist."

Fife & Dalton (2005) reviewed the genus.