the end of the stamen is the pollen box, or anther, from a Greek word for 

 flower. The anthers bear sticky or powdery pollen grains, which correspond 

 to the spores of simpler plants. 



The pollen grains resemble the spores of various kinds of simpler plants, 

 such as mosses and ferns (see illustration, p. 387). And Hke such spores they 

 normally give rise to a structure that corresponds to a gmnetophyte, as in mosses 

 and ferns (see page 385). But this is a very small plant that can be seen only 

 with a microscope, and so is easily overlooked. Moreover, this gametophyte, 

 which produces only a sperm cell and is therefore considered a male, carries on 

 its activities for the most part within a flower; and its short life ends in 

 fertilization. 



The ovule contains a large cell which we take to correspond to a spore that 

 gives rise to a jemale gametophyte. This completes its entire life as a parasite 

 within the ovule. For these reasons the pistil is sometimes spoken of as the 

 female organ of the flower. 



Where the corolla is a cup or tube, we can usually Where the petals are distinct, their number is usu- 

 make out a definite number of points or lobes, ally definite for a particular class — three or four 

 which we take to represent so many petals, as in or five, or a multiple of the number — as in 



Morning glory 



Potato 



Sunflower 



\ 



(\ 



^ 



Trillium 



Mustard 



Buttercup 



In "double" or other cultivated plants, like dahlias. Outside the corolla a group of greenish, leaflike 

 the number of petals may be very great, as in parts form a cup or calyx, as in 



Peony 



Buttercup 



Apple 



In some families of plants the calyx is hardly dis- And in many species of trees and grasses the en- 

 tinguishable from the corolla, as in velope is inconspicuous or entirely absent, as in 



Star grass 



Tulip Dogtooth violet Willow 



... ___i__ .. ■!■ ... ■ ■ . t. . 



401 



Oak 



Orchard grass 



