II4 BOTANICAL GAZETTE [AUGUST 
I wish to express my thanks to Dr. H. C. Cow.es and Dr. G. D. 
FULLER, University of ese who have aided me with suggestions 
and criticisms. 
Iowa STATE COLLEGE 
AmEs, Iowa 
LITERATURE CITED 
bal 
. Atway, A. J., Studies on the relation of the non-available water of the e. 
to the hygroscopic coefficient. Neb. Agric. Exp. Sta. Research Bull. 
1913. 
a. BAKKE; A. 4... cnet on the transpiring power of plants as indicated 
by the method « ygrometric paper. Jour. Ecol. 2:145-173. 
IQT4. 
, The index of foliar transpiring power as an indicator of permanent 
wilting in plants. Bor. Gaz. 60:314~319. 1915. 
. Bakke, A. L., and Livincston, B. E., Further studies on the foliar tran- 
spiring power in plants. Physiol. Researches 2:51-71. 1916 
Briccs, L. J., and SHantz, H. L., Application of wilting coefficient deter- 
minations in agronomic investigations. Proc. Amer. Soc. Agron. 3:250- 
256. 1912. 
, The bea coefficient and its indirect determination. Bor. 
Gaz. a 20-37. 
/<.ne RT wilting coefficients for different plants. Bot. Gaz. 
baa ade 1912. 
, The wilting coefficient for different plants and its indirect deter- 
minations. U.S. Dept. Agric., Bur. Plant Ind. Bull. 230. 1912. 
" .: Die snes Welkungskoeffizienten verschiedener Pflanzen. 
Flora 105:224-240. 1 
to. BURGERSTEIN, A., Die panate der Pflanzen. Jena. tor4. 
11. CALDWELL, J. S., The relation of environmental conditions to the phe- 
nomenon of permanent wilting in plants. Physiol. Researches 1:1-56. 
IQI3. 
12. Darwin, F., Observations on stomata. Phil. Trans. Roy. Soc. Lond. 
seein Gar. 1898. 
a self-recording method applied to the movements of stomata. 
Bor. Gaz. 37:81-103. 1904. 
14. DARwIN, F., and Pertz, D. F. M., New method of estimating the aper- 
ture of stomata. Proc. Roy. Soc. Lond. B. 84:136-154. 1911 
15. DetF, E. Marion, Transpiration in succulent plants. Ann. Botany 
26: 4090-442. I9I2 
16. Drxon, H. H. , Dranapiration and the rise of sap. Prog. Rei Bot. 3:1-66. 
1909. 
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