ECOLOGY OF FUNGI 75 



are active in rotting the brush, one set entering the Hmbs and branches 

 above the ground and the other gaining access to the brush actually 

 in contact with the soil. Brush is rotted at the top when piled 

 with one group of fungi and at the bottom by another group, while 

 the middle of the pile, not in contact with the soil and yet protected 

 from the sunlight, apparently will not rot to any extent until the 



Fig. 23.— Fairy ring formed by Marasmius oreades, an edible toadstool. (From 

 Wiley, Foods and Their Adulteration. After Coville, Circular 13, Division of 

 Botany.' 



pile disintegrates suflSiciently to expose these central layers to the 

 soil moisture on the one hand, or to the sunlight on the other. 

 Four fungi cause rotting of oak slash in Arkansas, viz., Stereum 

 rameale, S. umbrinum, S. versiforme and S. fasciatum. Two fungi are 

 responsible for the decay of short-leaf pine slash. They are Lenzites 

 sepiaria and Polyslictus abiet'mus.^ 



The xerophytic forms are those which have corky or leathery fruit 



^Lona, W II.: Investigation of the Rotting of Slash in Arkansas. U. S. Dept. 



Agric. Bull. 496, Feb. 16, 191 7; also Humphrey, C. J.: Timber Storage Conditions in 



the Eastern and Southern States with Reference to Decay Problems Bull, 510, U. 



S. Dept. Agric, May 17, 1917. 



