CROSS FERTILIZA TION 



77 



956. Since the publication of Darwin's remarkable investigations 

 upon the inter-relations of flowers and insects, it has been com- 

 monly supposed that the showy colors of flowers have been de- 

 veloped, or have originated, as a means of attracting insects, but 

 this explanation of the origin of colored parts is open to doubt. 

 But whatever the evolution of the corolla may have been, it is known 

 that color and perfume often attract insects. 



96. It is evident that 

 the insect would not visit 

 the flower for the flower's 

 sake, but for its own sake. 

 There must be something 

 in the flower which it wants, 

 for color and odor are only 

 attractions, not substantial 

 rewards. The things which 

 the insect wants are nec- 

 tar (or honey) and pollen, 

 chiefly the former. 



97. A flower of the 

 columbine (often erroneously 



called honeysuckle) is shown in Fig. 70. The 

 petals are produced into long spurs. If one of 

 these spurs were opened when the flower is in 

 full bloom, the bottom of it would be found to 

 contain a glistening secretion. This is the nec- 

 tar; and the spurs are, therefore, nectaries. 



FIG. 70. 

 Flower of columbine. 



97 a. Humming-birds are fond of sipping the nectar from the 

 columbine, for which their long bills are eminently fitted. Bees 



