Three new geophytic species of Pelargonium (Geraniaceae) from the Western Cape Province, South Africa and their relationships within section Hoarea

Abstract Pelargonium psammophilum E.M.Marais, Pelargonium naviculifolium E.M.Marais and Pelargonium montaguense E.M.Marais are described as new species. All are deciduous geophytes with turnip-shaped tubers belonging to section Hoarea (Sweet) DC. These three species share obovate to widely spathulate petals with narrow cuneate claws, undulate margins and prominent black blotches in the centre of the posterior two petals, acting as attraction points to the flower. However, they differ in leaf shape. Pelargonium psammophilum has erect, simple, lanceolate to finely divided leaves, P. naviculifolium has erect, simple, lanceolate leaves and P. montaguense has prostrate trifoliolate leaves with relatively long and thin petioles. The flower structure of the three species corresponds to that of Pelargonium heterophyllum Jacq., Pelargonium tenellum (Andrews) G. Don and Pelargonium trifoliolatum (Eckl. & Zeyh.) E.M. Marais. The six species are compared with regard to the flower and leaf morphology, palynology and chromosome numbers. They all occur in the winter rainfall region along the western and southern coast of the Western Cape Province as illustrated in the accompanied maps. The three new species described here are illustrated and a key for the identification of the six species with a P. heterophyllum flower type is also included.