The Ohio $J\Naturalist, 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
Volume XIV. FEBRUARY. 1914 . No. 4 . 
U8J», 
NEW \ 
HOT AN 
OAHU 
TABLE OF CONTENTS. 
Dachnowski— Transpiration in Relation to Growth and to the Successional and 
Geographic Distribution of Plants. . 241 
Drake— An Occurence of Atypus Milberti Walck. in Ohio.251 
Napper— Flood Erosion Along Paint Creek, Fayette County, Ohio.252 
Schaefner —Ecological Varieties as Illustrated by Salix Interior. . . 255 
TRANSPIRATION IN RELATION TO GROWTH AND TO THE 
SUCCESSIONAL AND GEOGRAPHIC DISTRIBUTION 
OF PLANTS.* 
Alfred Dachnowski. 
In former publications (Botanical Gazette 49; 325-339, 1910; 
Ibid 54; 503-514; Bulletin 16, Geological .Survey of Ohio, 1912) 
the writer invited a closer consideration of a number of points 
of interest to students of modern phases of Botany. Among 
other matters, attention was called to the fact that while the 
presence of structural modifications is generally regarded as a 
condition in favor of certain plants which are limited to habitats 
favorable to them, the more noteworthy characteristic is very 
likely functional variability, when plants extend the areal range 
beyond their typical habitats. It is a well known fact that 
plant migrations are not completed as yet, and that vegetational 
limits are determined more frequently by developmental than 
by climatic or edaphic conditions. European ecologists especially 
have furnished notable instances of this character, and the more 
important results of the several International Phytogeographic 
excursions into various parts of the world tend to give prominence 
to the problem of functional plasticity in plants of the same 
species, but of ecologically and geographically separate regions. 
Relative power of endurance and acclimatization are questions 
of special significance also in the existing peculiarities of scattered 
geographical distribution as well as in physiological ecology. 
* Contribution from the Botanical Laboratory of Ohio State University, 
No. SO. 
241 
