Schoenus coultasii (Cyperaceae: Schoeneae), a new annual species known from a single site in the Pilbara region of Western Australia

Schoenus L. is a large, cosmopolitan genus concentrated in the southern hemisphere, with more than 90 species in Australia (Wilson 1993). It comprises species that are either clearly perennial (the majority) or clearly annual, with a few others that are ambiguous in this regard but are possibly shortlived perennials. Under the modified sectional classification adopted by Musili et al. (2016: 267), the annual species are placed in sect. Helothrix (Nees) Kük.; however, they do not form a monophyletic group in the phylogenetic trees published in the same paper (Musili et al. 2016: 271, 272), apparently indicating that a change to the current infrageneric classification will be necessary.