May, 1911.] Evaporation Gradient in a Woodlot. 
349 
saturation deficiency from the lowest level upward. With the one 
exception of the reading of June 6-13, which is doubtful in its 
accuracy, and is further made unreliable on account of heavy 
rainfall during the week, a greater evaporation has occurred at the 
one foot level than at the three inch level. Bigelow* has pointed 
out a similar relation in evaporation from open pans over a sandy 
desert soil, and explains it by data which show that the temper- 
ature at the ground level was from one to two degrees higher than 
that at ten inches. It may be said, of course, that there is a 
marked difference between the sandy soil of the desert exposed to 
the rays of the sun, and the shaded forest floor. However, similar 
temperature phenomena have been observed in Cranberry bogs 
of Wisconsin f which have entirely filled the former lake basin. 
They consequently differ from the bog at Buckeye Lake in that 
they are not surrounded by an exposed water surface, and have a 
much lower water table. There is also a distinct difference 
between the vegetation cover with its high water table in the bog 
at Buckeye Lake, and the forest litter of our station. Temper- 
ature readings at the bog show a much greater range at the three 
inch level than at one foot or five feet. In the forest, the litter of 
leaves, and mold acts as an insulator and prevents rapid changes 
in evaporation, absorption, and radiation from the soil. A much 
more constant temperature might therefore be expected here, and 
a more uniformly low evaporating power of the air. Whether 
this explanation is sufficient to account for the difference pointed 
out, can not be stated with certainty. Further data are needed 
to throw light on the subject. 
*Bigelow, F. II. Studies on the phenomena of the evaporation of 
water over lakes, and reservoirs. Monthly Weather Review, U. S. Dept. 
Agr. 36:437. 1908. 
t Cox, H. J. Frost and temperature conditions in the Cranberry marshes 
of Wisconsin. U. S. Dept, of Agr. Weather Bureau. Bulletin T. 
NOTES ON NEW OHIO AGARICS III. 
Wilmer G. Stover. 
The following Agarics, collected at Oxford, Ohio, by the 
writer during 1909 and 1910, have not been previously reported 
for this state. 
Russula ochrophylla Peck. Pileus 5-9 cm., dark red or pur- 
plish red, convex, becoming depressed, dry, glabrous, smooth, 
margin even; flesh white, taste mild. Lamellae ochraceous yel- 
low, dusted with the spores, 6-S mm. broad, rather close, adnate, 
interspaces venose. Spores ochraceous, globose, eehinulate, 8-9 
microns. Stipe 4-7 X 1-2.5 cm., pale reddish, nearly equal, solid 
or spongy within. Growing on ground beneath beech trees. 
August. 
