A taxonomic revision of Crabbea Harv. (Acanthaceae: Barlerieae) in South Africa.

• A taxonomic treatment of Crabbea in South Africa is presented. • Updated genus and species descriptions are given, along with new delimitations. • Accurate distribution maps as well as ecological and habitat information is presented. • A new identification key is constructed. • Two taxa are reinstated to species level and three taxa are subsumed, thus, recognising five species of Crabbea in South Africa. The taxonomy of the South African species of Crabbea Harv. (Acanthaceae: Barlerieae) is reviewed and the following five species are recognised: C. acaulis N.E.Br., C. galpinii C.B.Clarke, C. nana (Nees) Nees, C. pedunculata N.E.Br. and C. velutina S.Moore. We subsume C. angustifolia Nees , C, hirsuta Harv. , C. cirsioides (Nees) Nees and C. ovalifolia Ficalho and Hiern under C. nana. All species are fully described and illustrated, with complete nomenclature, distribution maps and an identification key. One neotype and four lectotypes are designated. [ABSTRACT FROM AUTHOR]