THE \EGETATION OF THE SOUTHERN NAMIB. 



(Plate 4.) 



Bv R. Marloth. Ph.D., M.A. 



The designation " Namib " was originally applied only to the 

 desert plains situated between Walfish Bay and the grassveld 

 of the interior, which begins about jolj'miles from the coast. 

 Owing, however, to the great similarity of "the configuration of the 

 surface o" the land and the very insignificant rainfall.* which 

 in some years dwindles down to almost nothing, the country to 

 the North as well as the South of Walfish Bay possesses a fauna 

 and flora of the same character. And so the term has gradually 

 assumed a wider meaning and now includes the whole coastbelt 

 from the Cunene to the Orange River. In fact, a narrow strip 

 along the coast of Little Namaqualand. from the Orange River 

 as far South as the mouth of the Olifants River, also belongs to 

 it : hence the term Namib is really a convenient substitute for the 

 name " Western Littoral," employed by me on a previous occasion. 



The present paper is intended to deal only with that portion 

 of the Namib. which is traversed by the 27th degree of latitude, 

 and is consequently about 100 miles North of the Orange River. 

 The width of the Namib at this part is about 50 miles, being 

 bounded in the East by the escarpment of the highlands of Aus 

 and Kubub. which rise more than 2,000 feet above the plains of 

 the Namib and are nearly 5,000 feet above sea level. These moun- 

 tains and their western slopes possess quite a different vegeta- 

 tion, which, owing to the prevalence of some scrubby species of 

 Mesemhrianthcmnm and the occurrence of acacias along the river 

 beds, shows a great resemblance to certain parti of the Karroo, 

 especially its western parts. 



The Namib, on the other hand, is a waterless desert, in which 

 only a few spots are known where fresh water is obtainable, but 

 the vegetation of the Namib as a whole is richer and more diversified 

 than one generally thinks, the number of species as well as of typical 

 plant forms being very considerable. As an illustration, it may 

 be mentioned that I have observed over 20 species of Mesem- 

 brianthemuin, five species of Pelargonium (mostly shrubby), two 

 of Sarcocaitlon. three of Lycium, two of Zygophyllinn. two of 

 Sal sol a. three of Othonna, five shrubby Leguminosae {Leheckia 

 and Crotalaria), five species of Eviphorhia, and many other genera 

 represented by one or two species. 



In spite of the considerable number of species there are only 

 a few plant formations to be considered, for, apart from the wind, 

 they depend ujwn edaphic factors only, and these do not vary 

 much. Generally speaking, four formations may be distinguished, 



* Rainfall at Liideritzbucht (Angra Pequena) in the period 1904-5, 1.46 

 inches ; period 1905-6, 0.82 inch. 



Rainfall at Kubub, on the highlands east of the Namib : 1904-5, 4.65 

 inches; 1905-0. 1.75 inches. 



