WHEAT 



'309 



erage length being about 3J^ inches. The spike is also 

 variable as regards its form and compactness. It may be 

 tapering from the center toward both tip and base orfrom 

 the center toward the apex only. Again the spike may be 

 of uniform thickness throughout or, as in the 

 case of the club varieties, decidedly clubbed at 

 the apex. The number of spikelets-to a spike 

 is governed by variety, soil, cHmate, or culture, 

 the usual variation being from 10 to 20, con- 

 taining a total of 20 to 50 grains. 



380. The spikelets. — The spikelets may 

 be termed secondary spikes. Each spikelet is 

 joined to the rachis by a small branch which 

 extends through the center of the spikelet and 

 is known as the "rachilla." "Inserted on the 

 rachilla are several concave scales which are 

 called the glmnes. The two lowest and outer- 

 most of these contain no flowers or kernels 

 and are designated as the 'flowerless gliunes.' 

 Above these, arranged alternately, are borne 

 the flowers, rarely less than two, or more than 

 five. Each flower and, as it matures, each 

 grain, is subtended by a single glimie, known 

 as. the 'flowering glume.' Each flowering glume 

 has a longitudinal nerve which at the summit extends 

 (in the case of bearded varieties) into a prominent 

 'awn' or 'beard.' On the inner or creased side of the 

 grain or berry, filling it very closely, and more or less 

 hidden from view by the flowering glume, is borne the 

 'palea' or palet, a thin scale with two nerves. The flower- 

 less and flowering glumes and the palets are spoken of 

 collectively as the 'chaff.'" The wheat flower consists of 

 the flowering glume, the palea and the reproductive organs. 



Fig. 50. — 

 Front and 

 side viei* 

 of spikelet 

 of wheat, 

 showing 

 mode of 

 attach- 

 ment to 

 the rachis. 



