30 



THE SMALL GRAINS 



weakly undulating, glabrous, with very 

 short scarcely perceptible hairs on the 

 margin. 



33. The spike. The entire assem- 

 blage of floral organs on one culm is 

 called the spike. Each separate clus- 

 ter of these floral organs is known as 

 a spikelet. In wheat there is only one 

 spikelet at each node or joint. The 

 spikelets are arranged alternately on 

 the zigzag rachis, and transversely to 

 its median line. At the base of each 

 spikelet short bristly hairs occur. 

 These vary in color and length or may 

 be lacking. The spikes vary in length 

 from 2 to 5 inches, but are usually 3 

 to 4 inches. Spikes differ greatly in 

 form and degree of compactness. Some 

 are clubbed at the upper end while 

 others taper toward the apex or from 

 the middle toward both base and apex. 

 The spike may be square, or flattened 

 in the same plane with the spikelets 

 or transversely to the spikelets. Den- 

 sity, or the length of internodes of the 

 spike, is an important character, and 

 apparently a varietal characteristic. 

 The number of internodes to a deci- 

 meter is a good basis of calculation. 

 Taking 10 internodes at a time, a 

 good formula is D = 1000 -f- L, in 



FIG. 10. Turkey wheat plant, showing roots 7 

 feet long, grown at Nephi, Utah. 



