Bulbostylis itremoensis (Abildgaardieae, Cyperaceae), a new sedge species from Madagascar

Abstract

SummaryAn endemic species of Bulbostylis (Abildgaardieae, Cyperaceae) from Madagascar is described as new to science. Bulbostylis itremoensis is only known from two localities: the Itremo and Isalo massifs in the province of Fianarantsoa. The species can be recognised by its habit with numerous crowded culms, leaves and thick, soft roots with an outer mycorrhizal layer. Its culm is hairy, angular with about 10 rounded longitudinal ridges without conspicuous surface cells. The leaf sheaths are light brown to straw-coloured with numerous longitudinal nerves, densely short-hairy on the nerves but with numerous flexuose whitish hairs at their oblique orifices. Its inflorescence is a dense hemispherical head of c. 15 crowded spikelets with many erect or spreading involucral bracts. Its glumes are ovate, densely scabrid of which medium-reddish brown with a prominent 1 – 3-nerved green midrib ending below the obtuse apex or excurrent into a short mucro. This species is described, illustrated and compared to the other species of Bulbostylis that occur in the Itremo Massif Protected Area.