144 PLANT LIFE 



special adaptation to tide it over the dry, and 

 often hot, time of year it would be unable 

 to occupy such climatal regions. Often the 

 adaptation is fairly obvious. Thus, when the 

 rain falls on the South African veldt, in- 

 numerable leaves and flowers spring up as if 

 by magic. They flower and fruit, and then 

 disappear for the rest of the year. A re- 

 latively large proportion of this vegetation 

 consists of perennial plants of a bulbous 

 or tuberous character. As long as the dry 

 weather lasts they remain in a resting condi- 

 tion, the bulbs or tubers showing no sign of 

 life. If they be cut open, they are found, even 

 at this season, to be juicy ; that is to say, they 

 store water and retain it with great tenacity. 

 When conditions become favourable, the 

 leaves rapidly develop, and they are often not 

 at all the leathery or even succulent structures 

 one might expect to meet with. In fact they 

 frequently resemble those of typically meso- 

 phytic vegetation, and are thus simply 

 adapted for an average water supply, and 

 indeed such conditions do actually prevail 

 during their period of active growth. Their 

 food manufacture goes on rapidly, and the 

 surplus is stored up in the swollen portion, 

 so that when the growing, moist season is 

 over, they will have accumulated an amount 

 of easily utilisable food. It is the possession 

 of these qualities which enables them to 

 form underground the flowers and leaves 

 which will expand so rapidly on the return 



