456 



FUNGOUS DISEASES OF PLANTS 



the disappearance of starch, proteids, and cellulose suggests that 

 the fungus produces amylolytic, proteolytic, and cyteolytic enzymes." 

 A direct study of this point was attempted by making extractions 

 from fresh, young fruit bodies, and testing these. While this may 



not be an absolute criterion for 

 the basis of an opinion as to the 

 enzymes produced in the my- 

 celium, it is nevertheless inter- 

 esting that laccase, tyrosinase, 

 amylase, emulsin, protease, 

 lipase, rennetase, and coagu- 

 lase were seemingly present, 

 "whereas negative results were 

 obtained in the tests for pec- 

 tase, maltase, invertase, treha- 

 lase, and cytase. However, a 

 study of the destruction of wood 

 by the fungus furnishes evidence 

 that the mycelium produces cy- 

 tase and possibly hadromase." 



The sporophores arise singly 

 or in clusters of a few brackets, 

 usually during summer and early 

 autumn. It requires but a brief 

 period for these sporophores to 

 attain their growth, brackets 

 measuring 1525 cm. in width 

 having been observed to com- 

 plete growth within two weeks. 

 The mature sporophore is yel- 

 lowish brown above, and the 

 surface of the cap is thrown 

 into characteristic brown scales. 

 The plants are commonly 15-30 cm. broad, although one speci- 

 men measuring 65 cm. and weighing approximately six and a half 

 pounds has been found (Buller). The margins of the pileus are 

 slightly revolute even on maturity, the lower surface of the pileus 

 yellowish, with pores at first small, later expanding, and angular. 



FIG. 225. POLYPORUS SQUAMOSUS: PRO- 

 GRESSIVE DESTRUCTION OF WOOD 

 (After Buller) 



