Investigations at Lincoln, Nebraska. 



43 



On May 15, when the plants were 45 days old, a second examination was 

 made. They had an average height of about 4 inches and on most of them 

 the fourth leaf was fairly well developed. They had not yet begun to tiller. 

 The number of roots varied from 7 to 14, with an average of about 8. The 

 longer ones penetrated to depths of 1.6 to 2 feet, while the maximum lateral 

 spread did not exceed 0.5 foot. Some of the younger roots were only 1 to 4 

 inches long and without branches. They extended in a horizontal or oblique 

 direction, the longer ones sometimes being fairly well supplied with short 

 laterals of the first order. On the older roots, branches of the second order, 

 some nearly an inch in length, occurred, but they were not abundant. The 



primary laterals, especially in the surface 8 inches of soil, had reached a 

 length of 1 to 3 inches. Below 8 inches depth, only laterals of the first order 

 were found, and none exceeded 0.8 inch in length, while frequently the last 

 6 or 8 inches of the glistening white roots were entirely destitute of branches. 

 On seeds that were planted deep, a whorl of 4 to 6 roots had developed an 

 inch below the surface (fig. 18). The root system had a working depth of 

 about 7 or 8 inches. Thus, during this interval of 15 days, although growth 

 conditions were more favorable than before, the plants continued to develop 

 slowly. 



A 



8 



Fia. 18. — A and B. Oats 45 days old. 



