l60 SCIENCE IN AFRICA 



Mountain; memoirs of the Botanical Survey by Muir (1930) on 

 the Riversdale area, J. F. V. PhilHps (1931b) on the Knysna region, 

 and R. A. Dyer (1937) on the Albany region are important. Natal 

 and the Orange Free State are dealt with by Bews (191 2, 191 3, 

 191 7, 1920, 1921). Aitken and Gale (1921) describe the vegetation 

 of Natal and Zululand, and Bews and Aitken (1923) give the re- 

 sults of physiological experiments on the vegetation in relation to 

 light intensity, etc. For the Transvaal, Engler (1906) wrote an 

 account of the vegetation, Galpin (1927) has surveyed the Spring- 

 bok flats, and Mogg (1929) discussed the relationship of flora to 

 geologyin the neighbourhood of Pretoria. Furthermore Obermeyer, 

 Schweickerdt, and Verdoorn have contributed various papers on 

 the flora of the N. Transvaal (Annals of Transvaal Museum, 

 Bothalia, South African Journal of Science, 1933-7). For South- 

 West Africa there are old German works, notably by Schinz (1893), 

 Schenk (1889), and more recently by Dinter and Range. 



Southern Tropics 



For Southern Rhodesia Engler (1906) first described the vegeta- 

 tion. J. S. Henkel (1928) gave an excellent account of the relation 

 of vegetation to water-supply, and (1931) described the types of 

 vegetation in relation to other physical features such as geology, 

 soils, winds, rainfall and temperature, and in the same publica- 

 tion produced a reliable vegetation map of the territory. In rela- 

 tion to this w^ork H. B. Maufe (191 5) has described the Rhodesian 

 soils and their origin, as noted in Chapter V. For the neighbour- 

 hood of Salisbury, where overgrazing has altered the natural flora 

 materially, F. Eyles (1927) has contributed ecological notes of 

 value. In 1930 General Smuts and Dr. J. Hutchinson made an 

 extensive collection during the dry season from the Limpopo to 

 Lake Tanganyika, the results of which will appear in the latter's 

 account of his tour in South Africa. 



In Northern Rhodesia the distribution of vegetation has been 

 studied locally through the medium of air photographs. R. Bourne 

 (1928) has provided a list of the vegetational types encountered in 

 air survey, and found them coincident with soil colour and geologi- 

 cal formation in certain zones. E. Milne-Redhead in 1930 accom- 

 panied the ground control party of the aerial survey in Northern 



