Notes on the African genus Leptactina Hook.f. (Rubiaceae, Pavetteae).
A systematic revision of the genus Leptactina Hook.f. was conducted based on 1738 herbarium specimens from B, BM, BR, COI, G, K, LISC, MO, P, UPS, WAG, Z. Since 1871, 33 species have been described. We recognize 19 species, one of which is imperfectly known (L. petrophylax K.Schum.). Five more species are questionable due to the absence of nomenclatural types and one species (L. schubotziana K.Krause) is excluded. One subspecies, two varieties and three species are placed into synonymy. Two other species, previously considered as synonyms of L. platyphylla (Hiern) Wernham and L. laurentiana Dewèvre, are recognized at the rank of variety. An identification key is developed for the nineteen recognized species and, for each species a distribution map and a list of exsiccata is given.