The genus Isoglossa (Acanthaceae) in west Africa

Summary: The genus Isoglossa Oerst. (Acanthaceae) is revised in west Africa, with particular emphasis upon the Cameroon Highlands. Four species are recognised, including Isoglossa dispersa I. Darbysh. & L. J. Pearce newly described here, and a second new species for which further flowering material is required before description, here called Isoglossa sp. A. Lectotypes are chosen for I. glandulifera Lindau and I. nervosa C. B. Clarke and the status of the latter species in relation to the eastern African I. membranacea C. B. Clarke is discussed. The habitat, ecology and conservation status of each species are considered, and gregarious mass-flowering is reported in I. dispersa. © 2011 The Board of Trustees of the Royal Botanic Gardens, Kew.