Re-evaluating species limits in Uncinia angustifolia, U. caespitosa s.str., U. rupestris, U. viridis and U. zotovii (Cyperaceae)

摘要

Morphology of New Zealand hook sedges Uncinia angustifolia Hamlin, U. rupestris Raoul and U. zotovii Hamlin overlaps considerably, making species identification difficult. All three species have a complicated taxonomic history. U. angustifolia has been considered a variety of U. rupestris, which, in turn, has been considered a variety of U. caespitosa Boot or included in two other species. As for U. zotovii, this was originally part of U. caespitosa along with the grassland species U. viridis (C.B. Clarke) Edgar. The present study re-examines historical and recently collected material, and re-evaluates species limits for these five species using multivariate statistic analyses of morphological characters. Results confirm the circumscription of U. caespitosa s.str. and the segregation of U. viridis and U. zotovii from U. caespitosa s.lat., but they also indicate that current species descriptions are inaccurate and based on material of mixed identity. Results also suggest that U. angustifolia, U. rupestris and U. zotovii should be considered as three different species. U. viridis and U. rupestris are conspecific; the latter name has priority and should be maintained. An identification key, revised descriptions, new synonymy and distribution maps for the species recognised here are also presented.