10 BULLETIN 871, U. S. DEPARTMENT OF AGRICULTURE. 



persist in a dead fallen tree it is impossible to state, but the last 

 figure given indicates a rather extended period in some cases. These 

 cases refute the statements of Harkness (7) and Von Schrenk (26, 

 p. 75) that the mycelium does not grow after the death of the tree. 



On dead down trees the sporophores were never half bell shaped or 

 ungulate, but were more typically near the subapplanate type. 



Since so few cases of sporophores on dead fallen trees have been 

 recorded during a rather extended period, it is safe to assume that 

 infected fallen trunks are of slight importance from the standpoint 

 of forest sanitation in infecting living trees through the production 

 of sporophores. 



Although sporophores are rather rare, an accurate indication of 

 the place formerly occupied by a sporophore is supplied by the 

 shot-hole cup (PL II), so termed and described by Meinecke (15, 

 p. 23, 46). These shot-hole cups appear as cup-shaped depressions 

 below a knot, the depression being riddled with numerous fine holes. 

 At first they have the color of the freshly opened bark of the tree, 

 but later become weathered and gray with age. They are formed 

 in the following manner: The soft fleshly or cheesy sporophores 

 issuing through knots are usually soon eaten by squirrels and micro- 

 lepidopterous larvae. Some of these larvae then bore into the bark 

 of the tree, where they are sought after by woodpeckers, which 

 chop out a cup-shaped depression in the bark, corresponding to the 

 place formerly occupied by the sporophores. This depression is 

 riddled with what appear to be numerous fine shot holes, the burrows 

 of the insect larvae. 



The presence of a shot-hole cup is just as reliable an index of dry- 

 rot in a tree as is a sporophore. However, the same diagnostic 

 values in relation to the age of the fungus plant in the tree, and 

 consequently the extent of the resulting decay, must not be attached 

 alike to sporophores and fresh and old shot-hole cups. An old, 

 gray, weathered shot-hole cup would indicate the most extensive 

 serious decay, while a fresh shot-hole cup, in turn, would indicate 

 more extensive decay than a sporophore, since it is evident that 

 more time must elapse before a shot-hole cup is formed than a sporo- 

 phore and the longer the fungus plant lives in the heartwood the 

 greater the amount of decay resulting. 



The number of sporophores occurring on a standing living tree is 

 typically one. Von Schrenk (27, p. 205) gives the number as 

 usually one, but it must be remembered that at this time no descrip- 

 tion of Polyporus amarus had appeared, so it can not be stated 

 definitely that Von Schrenk was referring to this fungus. However, 

 -Meinecke (15, p. 46, pi. 12) gives the number as typically one. Some- 

 times two have been found. As many as five shot-hole cups have 

 been observed on a single living tree, but an examination of their con- 



