CHAPTER XIY. 



PLANT DEFENCES. 



Silver leaves are favourite souvenirs for strangers who visit 

 our shores. The stranger finds that the Silver Trees which 

 wave their welcome from Table Mountain are but the harbingers 

 of many surprises that await him in the plant world. The 

 climate of South Africa is different from that of an) other coun- 

 tries, and so plants look and behave differently. 



In many parts of this country plants have to do their work 

 principally in winter, as the summers are too hot and dry. In 

 the east and north winters are cool and dry, and plants have 

 a warm summer with rains in which to do their work. In other 

 parts it rains neither summer nor winter for months — even 

 years ; and to tide plants over these seasons of drought innum- 

 erable devices are found. 



In cold countries of the northern hemisphere, winter is the 

 sleeping-time of plants. When the leaves are cut off in the 

 "fall" of the year, they lie in sodden heaps beneath the trees 

 during the autumn rains and winter snows. In the spring 

 these leaves hold moisture and give it up slowly to the roots. 

 In this country very little decaying vegetation is left on the 

 ground. The ants could partly explain the reason if you asked 

 them. Have you ever watched them before a rain busily saw- 

 ing off twigs and carrying them underground '? Even burnt 

 matches are regarded valuable timber by them. The ants 

 change the conditions for plants both above and below the 

 soil surface.^ 



' It has been found that upon this material, some ants and termites 

 (so called white ants), cultivate vegetable gardens of fungi. These gar- 

 dens they tend so carefully that only one kind of a crop is grown in a nest. 



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