NATURAL ENEMIES OF THE FOREST. 



237 



External symptoms, to be observed especially in young specimens re- 

 cently attacked, consist in a change of the leaves to a pale sickly color and 

 often the production of short stunted shoots. A still more marked symptom 

 is the formation of great quantities of resin, which flow downward thru the 

 injured parts and out into the ground. (Forestry Bulletin No. 22, p. 51.) 



Of the irregular shaped fungi, one of the most destructive is a 

 true parasite, i. e. f one that finds lodgment without help, called Poly- 

 porus annosus and also Trametes radiciperda, Fig. 85. It is peculiar 

 in developing its fructifications on the exterior of roots, beneath the 



Fig-. 84. Honey Mushroom. Agancus melleus. 1. Cluster of small sporophores. 

 2. Larger sporophore with root-like organ of attachment. Forestry Bulletin 22. 

 Plate XII, Figs. land 2. 



soil. Its pores appear on the upper side of the fructifications. It 

 Attacks only conifers. 



Its spores, which can be readily conveyed in the fur of mice or other 

 burrowing animals, germinate in the moisture around the roots: the fine 

 threads of "spawn" penetrate the cortex, and spread thru and destroy the 

 cambium, extending in thin, flat, fan-like, white, silky bands, andj here and 

 there, bursting thru the cortex in white, oval cushions, on which the sub- 

 terranean fructifications are produced. Each of these is a yellowish-white, 

 felt-like mass, with its outer surface covered with crowded minute tubes or 



