Reproduction 



349 



203. The flower : essential structures. - - Richness of 

 color or striking form and fragrance in flowers may serve 

 useful ends leading toward reproduction. 



Moreover, in ornamental plants these 

 qualities often represent the crop value of 

 the plant. Beneath an apple tree in 

 spring the ground may be white, strewn 

 with discarded petals, representing much 

 energy of growth, that was, nevertheless, 

 serviceable. In seed production, however, 

 it is stamens and pistils which are directly 

 important, and the inconspicuous, unob- 

 trusive, or unattractive flowers of spinach, 

 lettuce, and corn are as effective as the 

 beautiful or gaudy structures of the 

 orchid and hollyhock. 



204. Pistil and stamen. - - The pistil 

 is commonly composed of one or more 

 carpels. Whether consisting of one or of 

 several carpels, it embraces in common 

 types (1) the ovule-sac, generally a 

 membranous or fleshy structure, contain- 

 ing at the time of flowering the relatively 

 small, seed-like ovules, or megasporangia ; 

 (2) a more or less well defined style, upon 



the terminal portion or surface of which is FIG. 93. Flower 

 differentiated (3) the stigma. of barley> 



The stamens consist in general of a stalk part or fila- 

 ment, supporting the anther, which latter contains the 

 anther sacs, or microsporangia, with their pollen-grains. 

 Stamens and pistil may be present in the same flower, 



