168 



ELEMENTS OP BOTANT. 



A little searcli among flowers, such as those of the colum- 

 bine or the foxglove, will usually disclose many which have 

 had the corolla bitten through by bees, which are unable to 

 get at the nectar by fair means and so steal it. 



206. Bird-Fertilized Flowers. — Some flowers with very 

 long tubular corollas depend entirely upon birds to carry 

 their pollen for them. Among garden flowers the gladiolus, 

 the scarlet salvia and the trumpet honeysuckle are largely 

 dependent upon humming-birds for their fertilization. The 



Fig. 151. —Flower-Frequenting Bird, with a Flower. 

 I, head of a sword-beak ; II, a datura flower, visited by it. (Both two- 

 thirds natural size.) 



wild balsam or jewel-weed and the trumpet-creeper are also 

 favorite flowers of the humming-bird. In Fig. 151 the head of 

 a flower-visiting bird and a flower frequented by it are shown. 

 207. Prevention of Self-Fertilixntion. — Dioecious flowers 

 are of course quite incapable of self-fertilization. Pistillate 

 monoecious flowers may be fertilized by staminate ones on 

 the same plant, but this does not secure so good seed as is 

 secured by having pollen brought to the pistil from a different 

 plant. 



