28 THE SMALL GRAINS 



sionally a fourth odd one. Still other branches put forth 

 near the bases of these, so that there are sometimes appar- 

 ently as many as 8 seminal roots, as in the variety Fultz. 

 Later the coronal or crown roots begin forming from nodes 

 just below the surface of the ground. The depth of the 

 seminal roots, therefore, depends upon the depth of plant- 

 ing, but the depth where the plant finally roots and feeds is 

 independent of the depth of planting. The coronal roots 

 rapidly divide into myriads of branches. There are 

 about eight branches to the inch, on each main root, to a 

 depth of 18 to 20 inches. Below this few branches are 

 found. It seems probable, therefore, that those roots 

 which go to such depths as 4 to 7 feet, as in semi-arid dis- 

 tricts, do so in search of water (Hays and Boss, 1899) 

 (Fig. 10). The roots start from the main axis apparently 

 in whorls of four each. The bulk of the plant-food is 

 obtained within a comparatively shallow depth, but 

 through an enormous root surface of divided and sub- 

 divided roots, covered with root-hairs. Winter wheat 

 roots will reach a depth of 116 cm. and spread laterally 

 126 cm., the root coefficient being 14616. Spring wheat 

 roots run 103 cm. deep and spread 104 cm., root coefficient 

 10712 (Rotmistrov, 1913, p. 25). 



31. Culms. In wheat the culms are hollow, but some- 

 times may be pithy within. They vary in height from 

 two to five feet, but in the driest seasons on the plains 

 may be even shorter. The same variety will vary in 

 height in different districts, on different soils, and with 

 different amounts of water. There is particularly great 

 variation in the length of the peduncle or uppermost in- 

 ternode, supporting the head. Wheat is generally taller 

 than barley and often taller than oats, but usually not so 

 tall as rye. The taller the plant, the greater the tendency 



