Vol. 40 No, 1 
BULLETIN 
OF THE 
TORREY BOTAN ICAL CLUB 
or 
JANUARY 10913 
Leaf water and stomatal movement in Gossypium and a method of 
direct visual observation of stomata in situ 
Francis E. Litoyp 
In a previous paper* it is shown that the rates of transpiration 
in cut shoots of the ocotillo, Fouguieria splendens, recorded by 
simultaneous volumetric readings and weighings, are not paraliel, 
but that the loss of water from the plant during the day is in 
excess of that taken up by the cut end of the shoot from the 
porometer. This result is in general harmony with the findings 
of Eberdtt with rooted plants of Helianthus annuus. It was not, 
however, found to be true in my study of the ocotillo that the loss 
of water takes place at a constant ratio during the hours of day- 
light, since the whole relation between the income and outgo may 
be reversed within a short space of time even during daylight by 
an apparently slight modification of the environmental condi- 
tions. This ready susceptibility of the plant lent color to the 
idea that the differences indicated by volumetric and gravimetric 
readings are measures of differences in the leaf moisture content, 
to be more briefly referred to as leaf water in the present paper. 
Determinations of the amounts of water held within the leaf at 
various times of the day, these being calculated in percentages 
of dry weight, showed that such: expected differences do occur, 
_ but the evidence was incomplete in that the amounts of leaf water 
were not calculated to a constant, since it must be assumed that 
sped BULLETIN for December 1912 (39: 567-631. pl. 40-45) was issued Jan. 2.] 
* The relation of transpiration and stomatal movements to the water-content 
of the leaves in Fouquieria splendens. Plant World 15: 1-14. Ja 1912. 
Tt See Burgerstein, A. Die Transpiration der Pflanzen 17. Jena, 1904. 
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