THE WATSONIA 79 



Evolution of Colored Flowers 



Something has been said in various preced- 

 ing chapters as to the philosophy of color vari- 

 ation. The origin of the colored floral envelope 

 is ascribed to the influence of insects. We have 

 been made aware that the floral envelope was 

 developed as an advertising device to attract in- 

 sects, that their services may be engaged for the 

 transfer of pollen that is so essential in keeping 

 up the necessary adaptability and vitality of a 

 race of plants. 



We have been led to infer that the floral en- 

 velope is one of the most recent developments in 

 plant evolution, inasmuch as the earlier forms of 

 plant life had no such apparatus and their suc- 

 cessors developed it only with the evolution of 

 the insect tribe. And we have doubtless been 

 correct in ascribing the ready variability of the 

 floral envelope to the fact of its relative newness. 

 The stalk and branches and leaves of the plant 

 have persisted, more or less modified in form 

 but essentially unchanged in functions, from the 

 remotest periods, and hence have attained a 

 fixed and determinate arrangement of their 

 hereditary factors that is diflficult to disturb. 



The conspicuous advertising sign that we call 

 a flower has been put forth so recently that it 



