984 
Journal of Agricultural Research 
Vol. XXXI, No. 10 
of;the ear. It would seem that any study of the growth of corn from 
the present standpoint should take account of the growth of the 
cob as a unit by itself. 
GROWTH-CAPACITY CONSTANTS OF SUNFLOWER AND CORN 
As a final comparison between the sunflower and corn equations, 
we may consider the growth-capacity constant A/R, As previously 
discussed, this constant is theoretically specifically related to the 
inherent or genetic characteristics of the organism. Since the formula 
seems to apply equally well to each of several constituents of the crop, 
Fig. 8 .—Growth of crude fiber in seed of sunflower per acre. Time (0 is reckoned in days from date of 
planting. Growth ( x ) is expressed as a percentage of 580 pounds. Equation to curve: 
log 5 g^“°-° 6 ° (£—103.5) . 
it may be presumed that the A/ K constant is of equal significance for 
the several constituents. Table I gives the values of the growth 
capacity constants. 
Table I .—Comparison of the growth capacity constants of certain constituents of the 
sunflower and corn crops 
Constituent 
A/Kn 10- 2 
Sun¬ 
flower 
Corn 
Crude fiber in stalk ® _ _ _ 
440 
97 
250 
165 
74 
1, 579 
Crude fiber in seed or ear _ _ 
Dry matter in seed or ear_ _ _ _ _ 
• Weighted average of first and second cycles 
From this table it appears that the sunflower is preeminently 
a crude-fiber or roughage crop, while corn is preeminently a grain 
crop. Comparing crude fiber in the stalk, the sunflower has greater 
