1 10 Deserts 



and the ice-plant carpets some of the most arid rocks 

 of Greece, even after months of drought, and looks, 

 too, just as deliciously cool as ever, its fleshy leaves 

 being still covered with their characteristic ' frosting,' 

 against which the hottest sun is powerless. On closer 

 examination the coating of 'frost' turns out to be 

 composed of innumerable globules of water contained 

 in the surface-cells — the skin — of the leaf. A prick with 

 a needle shows that these globules are just tiny bladders 

 filled with water ; but this skin is so exceedingly thin, 

 and so perfectly transparent, that it is a mystery how 

 the plants manage to keep their moisture; and it is 

 often no less a mystery how they manage to obtain it 

 in the first instance. 



An English meadow, again, would wither and turn 

 brown if it were left unwatered beneath the fierce heat 

 of a tropical sun, but the grasses of the Kalahari desert 

 Of South Africa remain surprisingly green, though 

 they get but one or two falls of rain in the course of the 

 whole year. Sometimes they get no rain at all for a 

 twelvemonth ; but even then, when they are the colour 

 of hay, they are equal to hay of ordinary quality as 

 fodder for cattle, and hence are of course still very 

 valuable. The wonder is how they manage to keep 

 any life at all, and any nourishment in them, after so 

 many months of burning drought. 



In parts of Texas, where also rain is quite the ex- 

 ception, the grass is often destroyed during the hot 

 months ; but other green things contrive to exist, and 

 these supply its place to the cattle. Timber is scarce 

 in these parts ; but within the last twenty years 

 thickets of ' mesquite ' have sprung up, and now cover 

 miles of prairie, where formerly there were none. And 



