410 BOTANICAL GAZETTE [ DECEMBER: 
4. CaSO, instead of Ca(No3),. 
ee oe ee ee Sa | 
— noice er oa eee ie 
5. K,SQO, instead of K, HPO, 
ssi } a - a an 3 : 3-58 
PP ee ie a a 
In measuring the “stem” (Spross) the average height of the 
longest leaves of all the plants in the culture was taken, hence 
the growth appears to have been more uniform than in any of 
the preceding tables, in which the length is computed only from 
the plants used at each time for the tests. The turgor of the 
“stem” (Stengel) was determined in the upper part of one of 
the older internodes, at a point where growth was assumed to 
have ceased. 
The difference in turgor between 1 and 1a would probably 
have been produced by the addition of the same quantity 
(0.0075 xq.) of any harmless salt, the action being probably 
purely physical. The cultures 3, 3a, 3b, and 1 form a series in 
which the K gradually increases without any change in the 
osmotic strength. The result shows a strikingly uniform grada- 
tion in both growth and turgor. Up to about the point of the 
normal solution an increase in the relative amount of K present 
was certainly beneficial to the plants, but doubling the K then 
present (3c) may not have had any more effect on the growth, 
or the turgor, than the addition of the same quantity of another 
salt (compare 1a). At the close of the experiment the only 
thrifty plants were in cultures 1 and 3c. All the plants in Ia, 
3, and 4 were dead, and those in 3a and 3b had only the yenee 
leaves and roots a omen a feeble show of life. 
CONCLUSIONS. 
ns ‘The testimony of the different experiments is so uniform, 
asd the ——— to be drawn are so ena and mans 
