200 BOTANICAL GAZETTE {MARCH 
crispum, T. capillaceum, Hymenophyllum hirsutum, H. polyanthos, 
and H. sericeum. At the close of 30 days of submergence these 
-were all thriving, and the contents of the cells were of normal 
appearance under the microscope, save in the case of H. sericeum. 
Its leaves were blackened and the chloroplasts disorganized and 
lumped together. This most drought-resisting of the forms worked 
with (the one which is least often completely wet in nature) is 
therefore the only species incapable of assuming an aquatic réle 
and having its transpiration stream stopped. Simultaneously 
with the above experiment, in which cistern water was used, an 
attempt was made to grow the same species in Sacus’s nutrient 
solution, diluted to half-strength, with fatal results to all of the 
cultures within the first week. 
ABSORPTION OF ATMOSPHERIC MOISTURE.—In the experiment 
regarding root-absorption, in which plants were kept with dry 
leaves in a moist atmosphere, it appeared possible that the sur- 
vival of the individuals used might be’in part due to the absorption 
of atmospheric moisture by the leaves. A test was made in whic 
10-15 leaves were cut from each of several species, sealed at the 
cut ends with vaseline, and dried at 70-80 per cent humidity until 
all the surface water was gone and the segments had just begun 
to curl. These were then laid on non-absorbent paper and placed 
in a small chamber kept moist with wet sheets of filter paper and 
clumps of sphagnum. The humidity was kept continually above 
95 per cent, and was usually nearer saturation. Several pieces 
of iron that happened to be available were placed inside, and 
together with the glass top to the chamber served to catch the 
condensation whenever the humidity approached saturation. 
Although an effort was thus made to prevent actual condensation 
of moisture on the leaves, a slight amount of it may have taken 
place, but if it did it is no more than might have occurred in nature, 
and it failed to prevent loss of weight by some of the species used. 
The following series of weighings was made by removing the leaves 
from the non-absorbent paper and placing them between large 
watch glasses; as the humidity of the laboratory was seldom below 
75 per cent, no great error was caused by the transfer. The first 
weight is that of the surface-dried leaves, the following ones being 
