THE STEMS AND FOLIAGE OF PLANTS, 37 



Plants growing in dry places, which cannot get 

 enough water, are often unable to make full-sized 

 leaves. The result is that while the "mid-rib" and 

 the side ones are developed, the pieces of the leaf 

 which ought to fill up the interspaces are not formed, 

 so that the whole leaf may be deeply cut down in 

 appearance. There is a common shrub used for hedges 

 about Cape Town and elsewhere, the leaves of which are 

 like a double comb. It is called Hakea, and came 

 from Australia. It is a member of the same family as 

 the Sugar-bush. 



One general result of a dry climate is to reduce the 

 size of the leaves greatly. Hence so many plants in the 

 Colony look like heaths, of which there are some 

 500 different kinds ; but as one goes eastwards to 

 Port Elizabeth and beyond, the climate is moister, and 

 they are much less numerous, partly from this, as well 

 as other causes, till they cease to occur altogether. 



The next thing to notice is, how often leaves are 

 hairy. Thus those of the silver tree ai-e densely clothed 

 with silky hairs. In memy cases the hair makes a 

 coating of wool, as on some of the Everlastiags. The 

 use of hair is to reduce the heat from sun, to lessen the 

 loss of water, and also to absorb dew for the benefit of 

 the plant when the rain or dew falls. 



Another result of drought is the hardening of the 

 woody parts so that the tips of leaves are often sharp 

 pointed ; and the shoots also are checked in theii' growth. 



