192 



BOTANY OF CROP PLANTS 



Spikelets and Flowers. — It was stated that the spikelets 

 usually occur in pairs. One is sessile, the other pedicelled. 

 The sessile one is broad, thick, and fertile; the pedicelled 

 narrow, long, and staminate. Whenever three spikelets are 

 in a group, one is sessile and perfect, and two are pedicelled 

 and staminate; sometimes one of the two stalked spikelets 

 may be perfect. 



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 endosperm-^ 



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Pig. 70. — Sorghum (Andropogon sorghum). A, pair of spikelets; B, grain in 

 section; C, grain, external. X 5. 



Fertile Spikelet (Fig. 71). — The sessile spikelet has thick, 

 leathery glumes of about equal length. The outer one par- 

 tially wraps about the inner. The latter is narrower and 

 more gradually tapering at the tip. Within the two glumes 

 of this sessile spikelet, are two flowers; the lower sterile, the 

 upper with both stamens and pistil. The so-called "third 

 glume" of some descriptions is the lemma of the lower, sterile 

 flower. Moreover, it is the only remnant of this flower. It 



