STAMENS AND PISTILS 



129 



are present). They are of two series. The outer series is 

 composed of the stamens. The inner series is composed of 

 the pistils. Stamens and pistils are 

 lomologous with leaves. 



;, ^ 270. Stamens bear 



200. Pistil of garden pea, 

 the stamens being pulled 

 down in order to disclose 

 it ; also a section, showing 

 the single compartment. 



207. Simple pistils of 

 buttercup, one in 

 longitudinal section. 



the pollen, which is 

 made up of a large 

 number of minute 

 grains. The stamen is 

 of two parts, as readily 



seen in Figs. 202, 203, 205, — the enlarged terminal part or 



anther, and the stalk or filament. The filament is often so 



short as to seem to be absent, and the 



anther is then said to be sessile. The anther 



bears the pollen grains. It is made up of 



two or four parts (known as sporangia or 



spore-cases), which burst and discharge the 



pollen. When the pollen is shed, the 



stamen dies. 



271. Pistils bear the ovules, which become 



seeds. The pistil may be of 



one part or compartment, or 



of many parts. The different 



units or parts of which it is 



composed are carpels. Each 



carpel is homologous with a 



leaf. Each carpel bears one 



or more seeds. A pistil of 



one carpel is simple; of two 



or more carpels, compound. 



Usually the structure of the 



pistil may be determined by 



cutting across the lower or 



seed-bearing part. Figs. 206, 207, 208 explain. A flower may 



contain one carpel (simple pistil) as the pea (Fig. 200); 



The structure of a plum blossom. 

 se. sepals; p. petals; sta. stamens; o. 

 ovary; s. style; si. Btigma. The pistil 



consists of I he ovary, style, :nnl Stigma. 



It contains the seed part. The stamens 

 are tipped with anthers, in which the 

 poUen is borne. The ovary, <>, ripens 

 into the fruit. 



