128 



BOTANY OF CROP PLANTS 



The percentage of hull in the upper grains of a spikelet is 

 less than that of lower grains. It is also stated that early- 

 ripening sorts have a greater percentage of hull than late- 

 ripening ones. The reports are conflicting concerning the 

 percentage of hull in short plump grains and in long slender 



em ma 



-rachilla 



s^rchv 

 endosperm 



Fig. 47. — A, mature grain of wild oats (Avena fatua); B, mature grain of 

 cultivated panicle oats (Avena sativa) ; C, grain of same with "hull " removed; 

 ZJ, cross-section of grain with the "hull." A.BandC, XS; D, Xio. 



ones. Furthermore, there is no constant relation between 

 weight of grain per bushel and per cent, of hull. However, if 

 an oat variety is well adapted to a certain region, the per cent, 

 of hull is quite generally lower than if it is poorly adapted. 



