2 Annals of the South African Museum. 



flora is still far from being exhausted. Such knowledge as has been 

 acquired in very many cases lacks precision owing to the poverty of 

 the specimens available for description and, further, on account of 

 the difficulties of travel and the remarkable power which the vegeta- 

 tion possesses of remaining dormant during the long spells of drought, 

 few localities are known with any degree of thoroughness. Much, 

 therefore, yet remains to be done in determining the geographical 

 range of species both within the region itself and beyond it into 

 contiguous areas. 



The further study of the vegetation of this tract of country — 

 nowhere thickly populated and to a large extent without settled 

 habitations — is greatly to be desired also for economic reasons. Its 

 most important permanent industry is pastoral, and it is only neces- 

 sary to direct attention to the fact that comparatively little is known 

 respecting its fodder plants and species poisonous to stock — which 

 are numerous. In this respect the grasses call for special notice. 

 The profusion of members of this family on the dry sandy plains of 

 Bushmanland is in itself remarkable, and the possibility of bringing 

 some of these into cultivation elsewhere for pastoral purposes is 

 worthy of attention. Other families which force themselves upon 

 the notice of the traveller include the Euphorbias which predominate 

 both in size and numbers over the rest of the vegetation throughout 

 extensive areas. These have attracted some attention as possible 

 sources of caoutchouc. The distribution and conditions of growth 

 of any of the Namaqualand Euphorbias may in the future become 

 questions of commercial importance. Agriculture is practised here 

 and there, frequently under somewhat primitive methods of irriga- 

 tion. There can be no doubt that with improved means of com- 

 munication and access to markets the cultivation of certain crops 

 is capable of further extension. These considerations furnish 

 economic justification for any efforts that can be made to obtain 

 a more complete knowledge of the composition of the native 

 vegetation and of the conditions under which it lives. 



In the furtherance of this object it is proposed to publish in the 

 following pages a list of the species represented in the collections 

 of the Percy Sladen Memorial Expeditions, with such additional 

 information from field notes and from other collections as may 

 seem desirable. A general discussion of certain prominent features 

 of the vegetation and of its relationships with contiguous floras 

 will be deferred until the determination of the species is com- 

 pleted. 



