The Angiosperms 183 



shown by all of the existing angiosperms, makes 

 it almost certain that they are all derived from some 

 common stock, or at any rate from a group of forms 

 closely related to each other. Once established, the 

 angiospermous type showed itself to be peculiarly 

 adaptable, and it rapidly assumed a predominant 

 position. Whence arose their extraordinary plas- 

 ticity can only be conjectured. The type of fruit, 

 with its complete protection of the seed until its 

 maturity, may have been one of the important fac- 

 tors in establishing this superiority over the cycads 

 with their exposed seeds, although it must be said 

 that in the cycads the growing seed is generally 

 more or less protected by the scales of the cone. But 

 this will not explain the extremely plastic plant body 

 which contrasts so strongly with the limitations of 

 the plant-body in the gymnosperms. 



It is possible that cross-pollination among the 

 angiosperms developed very early, and that thus 

 there was induced a greater degree of variability 

 resulting in the appearance of many modifications 

 which could be seized upon by natural selection, 

 and thus tend to develop new types. Whatever 

 may have been the reason, it is their extraor- 

 dinary adaptibility that is at the bottom of 

 the remarkable success attained by the angiosperms. 

 One very important phase of this is the utiliza- 

 tion of animals for distribution of pollen and 

 seeds. This is not absolutely confined to the angio- 

 sperms, as occasionally the spores of fungi are 



