Chapter XVII. 



Diseases of Timber and Shade Trees, Timber Rots 

 [Continued). 



Jg 



The shoe-string fungus rot [Agaricus (Armillaria) mellcus 

 BahlJ]. This fungus is also known as the honey-colored mush- 

 room. It is undoubtedly the most common of all of our fall 

 mushrooms. Its edible fruiting bodies may be found at the 

 base of almost any of our indigenous trees. They are very 

 frequent at the base of dead stumps, but may also occur on 

 the ground. They are usually found in dense clusters the lower 

 of which are covered with the fallen spore-powder from the up- 

 per fruiting bodies. The whole fruiting body, except the gills, 

 is more or less honey-colored hence its common name. The 

 stalk is usually swollen toward the base and carries near its sum- 

 mit a membranous remnant, the so-called annulus. The annu- 

 lus is usually conspicuous especially in the younger stage, but is 

 sometimes only slightly developed and occasionally entirely 

 wanting. The mushroom cap is lined on the under surface with 

 plates or gills which radiate out from the stem and bear the 

 spores. These are white and may often be found as a fine white 

 powder covering sticks and leaves under the fruiting bodies. 

 The honey-colored upper surface of the latter is covered with 

 fine, fibrillar scales of a darker color. These scales may also be 

 found on the young stem. When old the whole fruiting body 

 may become entirely smooth. 



At the base of the stipe may usually be found a shoe-string- 

 like strand of the mycelium from which the fruiting body orig- 

 inates. These strands which resemble small, leather shoe- 

 strings in appearance run long distances through the earth and 

 also occur just underneath the bark of trees where they 

 are usually somewhat flattened. The mycelium of the honey 

 mushroom may be parasitic on trees and is one of the most de- 

 structive of timber diseases. When the strand of a mycelium 



