dec z ( iyoy 
The Ohio -Naturalist, 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
LIBRAR 
NEW YOI 
BOTANIC 
QARDEF 
Volume X. DECEMBER. 1909. 
No. 2. 
TABLE OF CONTENTS. 
Dickey— Evaporation in a Bog Habitat 17 
Blair— The Orchitis of Ohio 24 
Zimmer — L ist of Insects Affecting the Maple 30 
Schaffner— N ew and Rare Ohio Plants 39 
A New Laboratory Guide for High School Botany T: 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 relatively 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 off 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 difficult 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. 
17 
