10 



FIRST BOOK OF GRASSES 



(the wild prairie rose with long styles). The calyx 

 and corolla are the floral envelopes; the stamens and 

 pistils are the essential organs of a flower, the parts 

 that produce seed. The floral envelopes protect 

 the essential organs in the bud and, by secreting 

 nectar which attracts insects or in other ways, com- 

 monly aid in securing the fertilization of the flower. 



The pistil consists of the 

 ovary, style, and stigma. 

 The ovary contains the 

 ovules, which when fer- 

 tilized develop into the 

 seeds. The style serves 

 to lift the stigma into the 

 air. The stigma is more 

 or less expanded, has a 

 viscid surface to which 

 the pollen-grains adhere 

 and upon which they ger- 

 minate, sending their con- 

 tents in a minute tube which pushes down through 

 the style to the ovules, fertilizing them. 



The grass flower (Fig. 3) is reduced to the essential 

 organs, the floral envelopes being represented by the 

 minute lodicules. Each flower is borne in the axil 

 of a small green bract (the lemma) and is subtended 

 and enveloped in a second bract (the palea). The 

 flower with its lemma and palea is termed the floret 

 (Fig. 4). The ripened ovary (the grain, or caryopsis) 

 (Fig. 5) consists of a small embryo lying at the base 



FILAMENT 



Fig. 3. Grass flower, showing sta- 

 mens and pistil and the rudi- 

 ments of floral envelope. 



