432 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9. 
The increase in ratio of tops to roots as the plants grow older is brought 
out in this experiment, as was the case for barley in Experiment I. Thus the 
results of Experiment III confirm in every way those obtained with barley. 
The three experiments leave no doubt as to the effect of nitrates in increasing 
the ratio of tops to roots in these two plants under the conditions employed. 
It is worthy of note, also, that there is little difference in the efficiencies 
of these two solutions as measured by total growth produced either in green 
or in dry weight. 
(Green Wt.) (Dry Wt.) 
In Series i, Sol. I, Total Growth 39.3199 3-8014 (low nitrate) 
Sol. II, " " 36.9930 3.2390 (medium nitrate) 
In Sei'ies 2, Sol. I, " " 49.4250 4.8440 
Sol. II, " " 54-6613 4.4670 
In Series 3, Sol. I, " " 61.4600 5-7998 
Sol. II, " " 61.5000 5-5905 
These figures show that plants in the higher-nitrate solution have 
relatively higher water contents and correspondingly smaller dry weights. 
In the light of this fact, there is great need of more careful consideration 
than is usually given as to what one desires of the plant before concluding 
as to the effectiveness of a particular solution or a particular fertilizer; also, 
dry-weight determinations which are not checked up occasionally with 
the green weights may be wholly misleading as to the actual amount of 
growth which may have taken place during a given period. 
Growth Features 
This was not a very favorable season for growing corn (February i- 
March 13), hence growth was slow, though the plants showed no external 
evidence either in tops or in roots of not being entirely healthy. No particular 
differences were noticeable in height or color of tops, but the roots in the 
low-nitrate solution were notably longer and larger from the first series 
(table 6). 
Experiment IV 
Effect of Increasing the Concentration of Nitrates upon the Ratio of Tops to 
Roots in Flax 
In the course of preliminary experiments, it was noticed that the ratios 
of tops to roots in certain plants were not appreciably altered by increasing 
the nitrate concentration of the solution. One of these plants was flax. 
Experiment IV was conducted, therefore, with flax to get more data on this 
point. A seed type of flax was used, one which had been selfed for several 
generations, thus assuring a certain grade of stability. 
The plants grew 41 days in the greenhouse simultaneously with the 
corn in Experiment III. They were green and healthy throughout, but 
