46 , THE MAMMALS OF ETHIOPIAN AFRICA 



certain other small trees and shrubs, and a clematis. The flora gradually changes 

 from the coast to the edge of the desert-like veldt and woods of the Kalahari itself, 

 partly in consequence of the varying water-supply and other conditions of the soil, 

 and partly owing to climate. A few miles from the coast with its struggling salt- 

 plants commences a range of hills and rocks, bearing only here and there small 

 colonies of short-lived plants, some half-buried in the sand. On the lee-side of the 

 rocks grows, however, a tall shrub-like plant about 5 feet in height with rod- 

 like branches, and thick, leathery leaves, known as Vectadium virgatum latifolium. 

 On the other side of the hills, where subterranean water occurs, vegetation is more 

 abundant, and there flourishes the melkbosch, a sappy euphorbia-like plant, always 

 accompanied by a stately parasite ; its dark grey bushes, 5 to 8 feet in height, being 

 dotted over the sandy plain like hay-cocks in a meadow. Farther east appear 

 thorny shrubs, which gradually become more numerous, and are eventually 

 accompanied by an aloe (Aloe dichotoma) ; and beyond this again, the country 

 slowly loses its desert-like character, and the acacia- woods and barren aristida- 

 plains of the Kalahari commence. 



On the open stretches of the karu deserts, or semi-deserts, of South Africa, 

 which attain a height of from 5000 to 6000 feet above sea-level, the vegetation is 

 of a richer and more varied type. The banks of the mostly dry river-beds are 

 covered, for instance, with dwarf acacias, and other kinds of bushes and shrubs ; 

 and, although mostly bare during the dry season, become green with bulbous 

 plants when fertilised by the warm spring rains ; the other vegetation consisting 

 of succulent plants and various ferns of a heather-like appearance. 



The most remarkable plant of this tract is undoubtedly Welwitschia mirabilis, 

 a plant discovered near Mossamedes by the traveller, Welwitsch, in 1860, but which 

 also grows abundantly around Walfisch Bay, as well as on the stony plains of the 

 coast. Its short, almost bulbous stem, devoid of branches, and clothed with a reddish 

 bark, rises only about 4 inches above the ground, but sends clown a long tap-root. 

 The summit, divided into two lobes and measuring as much as 13 feet in 

 circumference, is hollowed out like a dish, and bears on its edge a pair of long, 

 band-shaped leaves, standing opposite each other, these being the only leaves 

 developed, with the exception of the two seed-leaves, or cotyledons. During the 

 life of this strange plant, which seems to live for at least a century, the single pair 

 of leaves gradually wither and die towards the tips, but grow continuously from 

 the base. In young plants their edges are entire, but with increasing age they 

 become split up into crooked strips, lying irregularly on the ground. On the edges 

 of the discs are developed cones, the welwitschia being a relative of the conifers. 



While the welwitschia is restricted to the stony ground among the sand-dunes, 

 another remarkable desert-plant clothes their summits and slopes, namely, the 

 naras (Acanthosycios horrida), which attains a height of about 5 feet and belongs 

 to the same group as cucumbers and gourds. Its widely branched, green, solid 

 stems, are about an inch in thickness, and in the apex of the withered leaves 

 grow series of stout thorns arranged opposite each other. When its roots, which 

 are 4 inches in thickness and no less than some 50 feet in length, tap the 

 subterranean water of the desert, the plant soon rises above the loose sand by 

 which it is often buried, and so gradually becomes the centre of a hillock, the 



