20 



FLOWERS 



A study of Figure 16 shows that the base of the pistil is sur- 

 rounded by bracts, corresponding to those surrounding the 

 stamens in the staminate flowers. The bracts of the pistillate 

 flowers are small, membranous, and form the chaff of the cob. 



Oat Flower. — A head of 

 Oats, as shown in Figure 17, is 

 much branched and the spike- 

 lets occur at the ends of the 

 branches. Each spikelet con- 

 sists of two or more flowers, 

 which are well enclosed by the 

 two glumes. When the glumes 

 are spread apart as shown in 

 Figure 18, it is seen that the 

 flowers are attached, one above 

 another, to a small slender axis. 

 This axis is known as the ra- 

 chilla. Rachilla means small 

 rachis." Rachis is the name 

 applied to the main axis of 

 the Oat head from which the 

 branches arise. The small 

 branches bearing the spike- 

 lets at their ends are called 

 pedicels. Thus branches arise 

 from the rachis and end in 

 the rachilla to which the 

 flowers of the spikelets are 

 attached. 



The spikelet shown in Figure 18 contains three flowers, but 

 the upper one is rudimentary and, therefore, produces no grain. 

 There is one very important difference between the flowers of 

 Oats and those of Corn. In Corn the pistils and stamens occur in 

 different flowers, but in Oats the stamens and pistils occur to- 

 gether in the same flower. The Oat flower is, therefore, a perfect 

 or bisexual flower. In each Oat flower there is one pistil and 

 three stamens enclosed by the lemma and palea. The lodicules, 

 which are two small scale-like bracts at the base of the pistil and 

 stamens, are not easily seen in the Oat flower. The two glumes 

 of the Oat spikelet are so large that when closed together they 



Fig. 17. — Head or panicle of the 

 Oat plant, s, spikelets; 6, branches; 

 r, rachis; p, pedicels. About one-half 

 natural size. 



