156 



GROWTH AND WORK OF PLANTS 



little case, containing, when ripe, the pollen grains, very small, 

 free cells, which are produced in great numbers. In the butter- 

 cup these lobes open by splitting along the middle line on one 

 side, and permit the scattering of the pollen which to the eye 

 resembles a fine grained powder. The filament of the stamen is 

 attached along the inner face of the anther, and the latter in such 

 a case is said to be adnate. 



245. The pistils. The pistils are the members which occupy 

 the center or summit of the flower. They are numerous and 

 distinct from each other. 



The pistil is recognized as consisting of three parts, the ovary, 

 the style and the stigma. The ovary is the lower and larger part. 



It is ovate in outline and com- 

 pressed. The ovary is hollow, and 

 by cutting off one side a small body 

 is seen which is attached at the 

 base. This is the ovule in which 

 the embryo plant is formed after 

 fertilization, the ovule and embryo 

 together making the seed. The 

 style is the short, slender portion of 

 the pistil, and bears the stigma at 

 its apex. When the seed ripens the 

 ovary remains closed and firmly 

 forms a one-seeded fruit, which is 



Fig. 113. 



Young fruit of buttercup (R. acris) 

 after the sepals, petals, and stamens 

 have fallen. Section of pistil at right, 

 showing position of ovule. 



surrounds the seed. This 

 known as an akene. 



246. Complete flower. A flower like the buttercup, which 

 has all four series of members, is called a complete flower, and 

 because it has both stamens and pistils it is known as a perfect 

 flower. Because the petals are distinct from each other it is 

 called polypetalous, i.e., having many petals. Because all of the 

 parts are free and distinct (that is, not joined to other members, 

 or to members of the same set or whorl) it is a simple flower. 



247. The receptacle. The part of the flower to which these 

 different members are attached is the receptacle. The receptacle 

 is a more or less broadened end of the stem bearing the flowers. 



