256 BOTANICAL GAZETTE ? -  focToBER 
of the air are approximately uniform, the relative soil moisture 
conditions may be fairly well approximated by the criterion of 
water-holding power. The ease of obtaining comparative data 
for this factor entitles it to a thorough test as a soil criteriomy for 
habitat studies. 
THE Jouns Hopxrns UNIVERSITY 
Battmore, Mp. 
LITERATURE CITED 
. SPALDING, V. M., Distribution and movements of desert plants. Publ. 
113, Carnegie Institution of Washington. 1909. 
nt associations of the Desert Laboratory domain. Plant 
World 13: 231-42, 56-66, 86-93. 1910. 
. Livineston, B. E., The relation of desert plants to soil moisture and to 
eisnokation. Publ. 50, Carnegie Institution of Washington. 1906. 
, The relation of soils to natural vegetation in Roscommon and Craw- 
ford cpubties: beanie Bort. GAZETTE 39:22-41. 1905. 
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