CONTEXT AND PORES WHITE OR PALE. 



POLYPORUS BOREALIS (Fig. 668). Pileus sessile, dimidiate, 

 or sometimes growing more upright and reduced at base. Surface 

 hirsute- tomentose, particularly when young; when old, more matted. 

 Context white, tough, fibrillose, spongy when fresh, drying light 

 weight and fissile. Pores at first round (Fig. 669), angular with thick 

 walls, becoming, when mature, long, sinuate, daedaloid (Fig. 670). 

 Spores elliptical-compressed globose, 5x6 mic., hyaline, smooth. 



Fig. 668. Fig. 670. 



Polyporus borealis. Fig. 668, young pores (X6). Fig. 669, old pores (X6). 



In Europe this plant is well named, occurring in large quantities 

 in northern Europe, always on Abies. While a plant of common record 

 in more southern Europe (England), we doubt if they have it in 

 England, excepting perhaps in Scotland. In the United States we 

 have never seen it abundant, but it occurs in northern localities, and 

 we have one collection from Tennessee. 



As one first begins to notice Polyporus borealis in Sweden, it is a 

 round tubercule, then triquetrous and thick as it begins to develop 



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