STUDY OF A HEAD OF WHEAT 67 



central stem called the rachis. Each fully developed spikelet 

 has two or more grains and an undeveloped flower. When 

 only two grains develop in a spikelet each grain is enclosed 

 in an outer glume, a flowering glume, and a thin inner glume 

 called the palea. When a third kernel is present, it has no 

 outer glume, but is enclosed between the flowering glume 

 and palea. The germ of the kernel is at the base and faces 

 toward the outside of the spikelet; the creased side of the 

 grain faces toward the center of the spikelet and is covered 

 by the palea. Extending from the upper end of the kernel 

 IS a tuft of very fine hairs called the brush. 



