REPRODUCTION BY SEED 



335 



covering of sepals and petals, which may be brightly 

 colored, constituting a protection to the enclosed organs 

 during development and a means of attracting insect 

 visits after the flower opens, and, inside, stamens and 

 pistils. Examination of the pistil shows that within 

 it are the rudiments of seeds, called ovules. At the top 

 of the stamens are enlargements called anthers. Inside 

 them are small bodies known as pollen grains. In appear- 

 ance they resemble the spores of the fern and are in fact, 

 as we shall presently see, only a modification of them. 



Fig. 89. — Parts of a Flower TClarkia elegans). A, an open flower 

 showing (a) anthers, (p) petals, (st) stigma; B, open flower and 

 unopened bud, parts lettered as above in open flower. Bud covered 

 by sepals (s) and below the open flower the ovary (o), which con- 

 tains the ovules. 



It is well known to almost everyone that in seed repro- 

 duction it is necessary for the pollen to be placed on the 

 tip of the pistil, called the stigma, in order that fertiliza- 

 tion may eventually result and seed be produced. The 

 details which underlie this process are practically un- 

 known to the layman and need to be carefully studied 



