A comprehensive and authoritative guide to the indigenous succulents of South Africa, Botswana, South-West Africa (Namibia, Angola, Zambia, Zimbabwe) Rhodesia & Mozambique incorporating the latest research and changes in nomenclature
(1981)
Morphology, pollination and pollinators, ecology, phytogeography, hybridisation, keys and a systematic treatment of all African species : with a note on collecting and cultivation
(1980)