A synopsis of Ruellia (Acanthaceae) in Angola, including two species new to science

Abstract

A synoptic revision of the genus Ruellia L. (Acanthaceae: Acanthoideae: Ruellieae: Ruelliinae) in Angola is provided. Eight species are documented, including two species new to science, R. angolensis I.Darbysh. & E.Tripp and R. quipungoensis I.Darbysh. & E.Tripp, both of which are known from specimens collected between the 1930s-1970s. The affinity of the two new species is discussed; both are hypothesised to belong to sect. Discifolia E.Tripp & I.Darbysh.In addition, R. togoensis (Lindau) Heine, a rare species previously known from seasonally dry forests of west and west-central Africa, and R. praetermissa Lindau, a widespread west and central African species, are recorded in Angola for the first time. Full descriptions and accompanying notes on habitat requirements are provided for these species as well as for the localised Kaokoveld endemic R. currorii T.Anderson and the Angolan-Namibian form of R. bignoniiflora S.Moore. A key to Angolan Ruellia is provided. A preliminary assessment of the conservation status (extinction risk) is made for all of the species; the two new species are assessed as Endangered whilst the other six species are assessed as of Least Concern. The present account doubles the number of Ruellia species documented for Angola in the national plant checklist.