Studies in the genus Lotononis (Crotalarieae, Fabaceae). 13. Two new species and notes on the occurrence of cleistogamy in the section Leptis

Abstract

The occurrence of flower dimorphism in the genus Lotononis (DC.) Eckl. & Zeyh. is reported for the first time. Cleistogamous flowers have been observed in 12 species from four different groups of the sections Leptis (Eckl. & Zeyh.) Benth. and Oxydium Benth. Morphological differences between chasmogamous and cleistogamous flowers are discussed and illustrated. The phenomenon of flower dimorphism appears to be of limited taxonomic value but nevertheless supports the idea of an affinity between the  L. laxa, L. pungens and  L. leptoloba groups. Two recently discovered new species of the  L. leptoloba and L. calycina groups,  L. venosa B-E. van Wyk and  L. acuticarpa B-E. van Wyk, are described.