100 
DESERT VEGETATION. 
Chap. V. 
gryllus of the same colour feeds on it. In the case of the insect, 
the peculiar colour is given as compensation for the deficiency of 
the powers of motion to enable it to elude the notice of buds. The 
continuation of the species is here the end in view. In the case of 
the plant the same device is adopted for a sort of double end, viz. 
perpetuation of the plant by hiding it from animals with the view 
that ultimately its extensive appearance wiU sustain that race. 
As this new vegetation is better adapted for sheep and goats in 
a dry country than grass, the Boers supplant the latter by imi¬ 
tating the process by which gramnivorous antelopes have so 
abundantly disseminated the seed of grasses. A few waggon¬ 
loads of mesembryanthemum-plants, in seed, are brought to a 
farm covered with a scanty crop of coarse grass, and placed on a 
spot to which the sheep have access in the evenings. As they 
e^t a httle every night, the seeds are dropped over the grazing 
grounds, in tliis simple way, with a regularity which could not be 
matched except at the cost of an immense amount of labom\ 
The place becomes in the course of a few years a sheep farm, as 
these animals thrive on such herbage. As abeady mentioned, 
some plants of this family are furnished with an additional con¬ 
trivance for withstanding droughts, viz. oblong tubers, which, 
buried deep enough beneath the soil for complete protection from 
the scorching sun, serve as reservoirs of sap and nutriment during 
those rainless periods which recur perpetually in even the most 
favoured spots of Africa. I have adverted to this pecuharity as 
often seen in the vegetation of the Desert; and, though rather 
out of place, it may be well,—while noticing a clever imitation of 
one process in nature by the Cape farmers,—to suggest another 
for their consideration. The country beyond south lat. 18° 
abounds in tlmee varieties of grape-bearing vines; and one of 
these is furnished with oblong tubers every three or four inches 
along the horizontal root. They resemble closely those of the 
asparagus. This increase of power to withstand the effects of 
chmate might prove of value in the more arid parts of the Cape 
colony, grapes being weU known to be an excellent restorative in 
the debility produced by heat; by engrafting, or by some of 
those curious manipulations which we read of in books on garden¬ 
ing, a variety might be secured better adapted to the country 
than the foreign vines at present cultivated. The Americans 
