IlxjIlibrar Y 



The Ohio ^aturaliM^r^ 



PUBLISHED BY 



The Biological Club of the Ohio Stale Uni'versity. 

 Volume X. DECEMBER, 1909. No. 2. 



TABLE OF CONTENTS. 



Dickey— Evaporation in a Bog Habitat 17 



Blair— 1 he Orcliids of Ohio 24 



ZiMMER— List of Insects AttVeting the Maple 3i> 



ScHAFFNER— New and Rare Ohio Plants 39 



A Xew Laboratory Guide for High School Botany 40 



EVAPORATION IN A BOG HABITAT.* 

 Malcolm G. Dickey. 



Within the past two years, investigations have been carried 

 on at a bog island in the Licking Reservoir near Columbus, Ohio, 

 disclosing the toxicity of bog water, and bog soils. The physi- 

 ological aridity of this bog habitat has been discussed in two 

 papers, (1 and 2). In connection with experiments, which are to 

 be made upon the transpiration of bog plants, it was thought 

 desirable to obtain direct evidence concerning the evaporating 

 power of the air of this region. With this object in view, the 

 data given below were collected during the past summer. 



The problem of evaporation, though manifestly an important 

 one, has received relativelv little attention. Recent investiga- 

 tions at Salton Sea in Southern California, have brought to the 

 attention of meteorologists, the vital importance of evaporation 

 in the storage of water in reservoirs, for irrigation purposes in the 

 arid regions of the west. Salton Sea, which is cut ofif from the 

 Colorado River, must, in the course of ten or twelve years, it is 

 estimated, be reduced by evaporation, and it is planned, there- 

 fore, to make a complete study of the phenomenon in that 

 region. Readings are taken from floating tanks and pans upon 

 water surfaces at different points on the sea, and likewise at 

 auxiliary stations in different climates and under different 

 conditions. 



Considered purely from a physical standpoint, evaporation 

 depends upon humidity, temperature, and wind velocity. The 

 sun's rays influence it only as they increase the temperature of 

 the air and of the evaporating surface. Secondary factors influ- 

 encing evaporation are, however, so numerous, and difflcult to 

 separate, since they all may operate at the same time, that it is 



* Contributions from the Botanical Laboratory of Ohio State Univer- 

 sity, L. 



