122 FOREST PROTECTION 



IX. Polyporus nigricans attacks beech, birch and poplar 

 in the New England States causing standing 

 timber to rot. (Agric. Year Book 1900, p. 207; 

 Bulletin Bureau Plant Industry No. 149, p. 42). 

 X. Polyporus sulfureus causes the brown rot of many 

 conifers, also of oak, walnut and cherry. (Bull. 

 Bureau Plant Industry No. 149, page 37; Agric. 

 Year Book 1900, p. 207). 



XI. Polyporus igniarius occurs everywhere on beech and 

 oak. (Agric. Year Book 1900, p. 207; Bulletin 

 Bureau Plant Industry, No. 149, pp. 25 to 37). 

 XII. Polyporus libocedris causes the peckiness of bald 

 cypress and the pin rot of incense cedar. The 

 pecks consist of disconnected holes (or pockets) 

 about 4" long ending abruptly and partially 

 filled with brown powder. Found in trees over 

 100 years old. Reference: Contr. Shaw School 

 of Botany, No. 14. 



XIII. Polyporus pinicola. Western conifers, four years after 



death, are found entirely destroyed by Poly- 

 porus pinicola. Reference: F. & I., 1902, p. 60; 

 Agric. Year Book 1900, pp. 202 and 209 and 

 plate XXV. 



XIV. Polyporus obtusus is a common cause of the sap rot 



in dead oak trees (Bull. Bureau of Plant In- 

 dustry, p. 41). 



XV. Polyporus fulvus causes the so-called "red heart" 

 of the birch (Bull. Bureau of Plant Industry, 

 p. 47). 



XVI. Polyporus squamosus causes "white rot" in various 

 hardwood trees, e. g. maple, oak, beech, birch 

 and ash. (Bull. Bureau of Plant Industry, p. 48). 



XVII. Polyporus pergamenus causes the "sap rot" of trees 



and logs often after fires in many hardwoods 

 (notably oak); its work is particularly quick, and 

 so is the rapidity of its fruiting (Bull. Bureau of 

 Plant Industry, No. 149, p. 56). 



XVIII. Polyporus betulinus and fomentarius may parasiti- 



cally weaken living birches and beeches (Mayr), 

 or may be satisfied to cause the decomposition 

 of weakened and of dead wood (Von Schrenk). 

 (Bull. Bureau of Plant Industry, No. 149, p. 49). 

 XIX. Polyporus applanatus is reported as the killer (?) of 

 cottonwoods (Bull. Bureau of Plant Industry, 

 No. 149, p. 58). 



