A reconsideration of Pleurophascum (Musci: Pleurophascaceae) and specific status for a New Zealand endemic, Pleurophascum ovalifolium stat. et nom. nov.

The taxonomy of and relationships between the three taxa described in the genus Pleurophascum are reconsidered. P. grandiglobum is confirmed as a Tasmanian endemic. The New Zealand taxon, heretofore known as P. grandiglobum var. decurrens, differs from the Tasmanian species by numerous morphological characters, including capsule shape, size, and pigmentation; leaf shape; and degree of reflexion of the leaf margins. The New Zealand taxon is given specific status as P. ovalifolium stat. et nom. nov. Both P. grandiglobum and P. ovalifolium have laterally borne sex organs that are not subtended by innovations. Recently discovered fruiting material of the Western Australian endemic P. occidentale differs from both P. grandiglobum and P. ovalifolium by having terminal sex organs, short (c. 1 mm) setae, and nearly sessile, obovoid, and non-rostrate capsules that lack stomata. Distribution maps and a key to the species are provided. The larger relationships of the genus Pleurophascum cannot yet be resolved. © The Royal Society of New Zealand 2005.