A monograph of the genus Ornithoglossum (Liliaceae)

An account is given of the morphology and taxonomy of the African genus Ornithoglossum Salisb. The genus belongs to the Liliaceae–Wurmbeoideae, a phytochemi–cally distinct taxon sometimes treated as a separate family, the Colchicaceae. Ornithoglossum belongs to the tribe Iphigenieae, which is here amended to include the former tribe Glorioseae. Within the genus Ornithoglossum 8 species are here recognized, 3 of which are new, viz. O. parviflorum B. Nord., O. vulgare B. Nord. and O. gracile B. Nord. Two varieties of O. parviflorum are recognized. O. zeyheri (Baker) B. Nord. is a new combination. The chromosome number 2n = 24 is recorded for four species. The genus is believed to have originated in formerly arid regions of tropical Africa. Because of a climatic change, an increase in humidity, a south– and southwestward migration took place, followed by speciation in response to factors in the new environment. Sympatric speciation may have been promoted by the development of differences in flowering times and by specialization to different pollinators. The evolution of the nectary region of the tepals is particularly illuminating, and taxonomically useful. The proposed taxonomy is further supported by ultrastructural features of the seeds and pollen grains.