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 
Fig. 17.— Head or panicle of the from the rachis and end in 
lant. spikelets; b, branches; . : 
ae Pp, ce eae el the rachilla to which the 
sa hanal eee 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 Jarge that when closed together they 
