Semi-Centennial Volume. 139 



ROOT SYSTEMS. 



The root systems of Pride of Saline corn, Blackhull kafir and Dwarf 

 milo plants, which were grown in alternate rows, were isolated in the 

 field at four stages of growth in 1914, and at three stages of growth 

 in 1915. All told, the root systems of thirty-three plants were isolated 

 and studied. It was found that for a given stage of growth each plant 

 possessed the same number of primary roots, and that the general ex- 

 tent of these roots in both a horizontal and vertical direction was the 

 same for all three plants. The maximum depth of root penetration for 

 mature Dwarf milo, Blackhull kafir and corn was found to be six feet 

 for both the years 1914 and 1915. It was found that Blackhull kafir 

 and Dwarf milo possessed approximately twice as many .secondary roots 

 per unit or primary root as did the corn plant. This was true, not only 

 for both years, but also for all stages of the root systems examined. 

 Both the primary and secondary roots of the sorghums were found to be 

 more fibrous than those of the corn plant, 



LEAF AREA. 



The average leaf areas of five representative plants of corn, Black- 

 hull kafir and Dwarf milo, were obtained at stages when the plants were 

 four, six, eight and ten weeks of age. The last stage examined showed 

 that the plants had completed their full leaf development. In all stages 

 of growth the corn plant was found to have the greatest leaf area. Tak- 

 ing the stages of growth in order, one finds that the leaf area of the corn 

 plant was 1.7, 2.0, 2.2 and 2. .3 times the leaf area of Dwarf milo, and 1.6, 

 1.9, 1.5 and 1.5 times that of Blackhull kafir. 



VARIATION OF WATER AND DRY MATTER IN THE LEAVES. 



The variation of the water and dry matter in the leaves of corn and 

 the sorghums was determined by nine experiments in 1914, two in 1915 

 and four in 1916. These experiments were conducted with plants of 

 Pride of Saline corn, Blackhull kafir and Dwarf milo, which were gi-own 

 in the field either in a series of plots, or in alternate rows on the same 

 plot. Four of the experiments in 1914 extended only through the 

 daylight hours, but all the other experiments ranged in length from 

 twenty-four to forty-eight hours. In these experiments the water and 

 dry matter in the leaves were determined every two hours during twenty- 

 two days and ten nights. The amount of water in the leaves of milo was 

 found to be much lower at all times of the day and night than that of 

 either corn or kafir leaves at a like stage of development, while the 

 average water content of the corn and kafir leaves at the same age was 

 practically the same. The water content of the leaves of corn, kafir and 

 milo averaged 118, 129, 107 gms., respectively, for each square meter of 

 leaf during the day periods, and taken in the same order, 128, 133, and 

 116 gms. for the night periods. The average range between the maximum 

 water content of the leaves during the night and the minimum amount 

 during the day was 24 gms. for corn, 26 gms. for kafir and 22 gms. 

 for milo. 



The dry weight of a given area of milo leaf was always found to be 

 greater than an equal area of either corn or kafir leaves at the same 



