Southern Africa is certainly not a naturally bounded area so that there are several possibilities for delineating it and concepts about its extent. Wellington* discussed the various possibilities for delineation and suggested that one line stands out more clearly and definitely as a physical boundary than any other, namely the South Equatorial Divide, the watershed between the ZaIre, Cuanza and Rufiji Rivers on the one hand and the Z ambezi, Cunene and Rovuma Rivers on the other. This South Equatorial Divide is indeed a major line of separation for some organisms and is also applicable in a certain geographical sense, though it does not possess the slightest significance for many other groups of organisms, ecosystems or geographical and physical features of Africa. The placing of the northern boundary of southern Africa differs in fact strongly per scientific dis cipline and is also influenced by practical considerations regarding the possibilities of scientific work as subordinate to certain political realities and historically grown traditions. This is illustrated, for example, in such works as the Flora of Southern Africa, where the northern boundary of the area is conceived as the northern and eastern political boundaries of South West Africa, South Africa and Swaziland. Botswana, traditionally included in the area covered by the Flora Zambesiaca, thus forms a large wedge in 'Southern Africa'.

This text gives biographical accounts of the leading plant collectors and their activities in Southern Africa from the days of the East India Company until modern times.

Vols. 16-21 include supplement: British empire vegetation abstracts.

In 1951 UNESCO launched an Arid Zone Programme with the object of promoting research into arid regions from every relevant scientific point of view. This book, originally published in 1966, represents the range of research undertaken and gives a general conspectus of arid zone geography. 17 authors from 8 countries contributed and the book deals comprehensively with all the main areas, with specific examples used to illustrate arguments. There are chapters on meteorology, geology, geomorphology, botany and zoology and almost 50% of the book is devoted to man’s activities: irrigation and agriculture; industry; animal breeding and human survival in the desert