140 



FUNDAMENTALS OF AGRICULTURE. 



when the roots, culms and leaves only are considered, 

 the resemblance ceases when the seed head is exam- 

 ined. Instead of a loosely constructed branched pani- 

 cle we find a more or less compact, unbranched head, 

 called a spike. The spikelets that form the wheat 

 head are arranged alternately at the joints of the stem, 

 and the joints are short and very closely set. The 

 portion of the stem which bears the head is bent or 



TYPICAL WHEAT GRAINS. 



hollowed out on the side next to the spikelet until we 

 have a zigzag effect. This portion of the stem is 

 known as the rachis. There is but a single spikelet 

 at each joint of the rachis, and these spikelets may be 

 closely set or somewhat apart from each other. This 

 gives quite a variation betv/een varieties, since some are 

 remarkably compact, while others are very loosely con- 

 structed. It is by no means the varieties with com- 

 pact spikes that always give the heavier yields of grain, 

 for there is a wide variation even between varieties 



