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! 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 Bucke}'e 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 unifomily 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. 



*Bigelo\v, F. H. Studies on the phenomena of the evaporation of 

 water over lakes, and reservoirs. Monthlv 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, echinulate, 8-9 

 microns. Stipe -1-7X1-2.5 cm., pale reddish, nearly equal, solid 

 or spongy within. Growing on ground beneath beech trees. 

 August. 



