Cliutbing Plants and Plant Migrations I 29 



The "Port Jackson Willow," from Australia, is admirably 

 adapted to aid in this work. Besides spreading by the count- 

 less seeds which it produces, the plant multiplies by tough 

 suckers, that run underground in all directions, forming a firm 

 foundation upon which their humus or decaying leaves mingle 

 with the verdureless sand. Moreover, these plants belong to 

 the great group of leguminous plants, the nitrogen gatherers. 

 Their innumerable roots are claiming quantities of the valuable 



Fig. 117. — Mvrii-a cordlfolia, L. (Photograph by Dr. Marloth.) 



nitrogen of the air, and are giving wealth to the soil as fast as 

 it is being removed from the Kimberley and Johannesburg 

 mines (See p. loi.) 



Plants introduced into America have spread until they have 

 become pests. The same plants brought to this country for 

 their beauty of flower may grow, but seldom become noxious. 

 South Africa, with its wealth of beautiful flowers, can well 

 dispense with introduced flowers, except the Roses and Violets, 

 which are lacking in this country — and how they do thrive ! 



The lack of fuel and building timber in South Africa is not 



9 



