2J:4 EVOLUTION OF PLANTS 



struggle for existence largely to the perfect provision 

 for the distribution of their seeds which they have de- 

 veloped. Every animal which brushes against one of 

 these plants covered with its ripe fruits, carries away its 

 quota of seeds, to dislodge them far away from the place 

 where they grew. In this way many plants have been 

 carried from their European home to all quarters of the 

 globe, and where the conditions are favorable, have 

 quickly taken possession of the new territory. 



The extraordinary variety shown by the flowers of 

 Angiosperms is intimately associated with the question 

 of cross-fertilization through the agency of animals, 

 mostly insects ; and the extraordinary development of 

 certain groups of insects is the result of a reciprocal 

 adaptation. 



There is little doubt that the first flowers were very 

 simple, probably not unlike those of certain low types 

 still existing, and consisted of a single carpel or sta- 

 men, or perhaps a group of sporophylls, without any 

 trace of the showy corolla found in the higher forms. 

 The simple flowers of the aroids, pond-weeds, peppers, 

 willows, and others (Figs. 43, 45, 49), are examples of 

 such flowers, and whether this simplicity is primitive or 

 secondary, some such forms must have been the starting-- 

 point from which proceeded the development of the 

 specialized flowers of the higher groups of Angiosperms. 

 Such simple flowers are usually quite dependent upon 

 chance for the transfer of the pollen-spores to the stigma, 

 and with the exception of a few aquatic forms, the agency 

 by which this is effected is the wind ; hence these flow- 

 ers are called " anemophilous," or wind-fertilized. These 

 anemophilous flowers are always inconspicuous and odor- 



