DISEASES OF BOOTS, ETC. 43 



RING SCALE FUNGUS. 



The ring scale fungus (Trametes pini pronounced 

 trameeteez) causes one of the most destructive diseases 

 of living mature and overmature conifers. Though the 

 perennial fruiting bodies reach a great age 50 years or 

 even more they are seldom very large, and vary in 

 shape according to the host they grow upon. (Pis. IV 

 and V.) As a rule they are irregular, hoof -shaped, the 

 upper side grayish black, rough, dull, often cracked, 

 with concentric furrows parallel to the rather conspicu- 

 ous narrow, velvety, light brown margin. The under- 

 side is light grayish brown. The pores are very large 

 and irregular, varying from relatively small, angular 

 ones near the margin to long, sinuous holes forming a 

 maze with irregular meshes. The substance of the 

 fruiting body is rusty brown in color, and cuts like 

 cork. On the pines the fruiting bodies grow out 

 through branch scars, and, as a rule, only one or a very 

 few of larger size are developed. On white and red 

 fir they are generally smaller. On Douglas, white, and 

 red fir they often form directly on the bark, usually in 

 large numbers. Because of their inconspicuous coloring 

 they are easily overlooked. The mycelium spreads rap- 

 idly up and down the tree. A cross section of the heart- 

 wood shows that certain annual rings are more affected 

 by the fungus than the others, hence the name " ring 

 scale " (PI. VI), and also that the action of the fungus 

 is confined almost entirely to the soft springwood of the 

 annual ring, though the color of the hard summerwood 



