AUTOBASIDIOMYC1 



463 



Polyporus borealis (Wahl.) Fr. is a characteristic and destructive 

 disease of the spruce in Europe, and it occurs on a variety of conifers 

 in America. 1 The bracketed sporophores are clustered, as shown 

 in Fig. 228. They are fleshy for some time, but finally tough and 

 dry. The spores are minute, measuring 4-5 x 3 p. The mycelium 

 develops abundantly in the wood with typical markings (Fig. 229). 



FIG. 229. POLYPORUS BOREALIS: L<.>N<;iTrni.\.\i. SECTION OF LOG, 

 SHOWING MYI-KLUM. (Photograph by Geo. F. Atkinson) 



Polyporus carneus Xees causes a red rot, or peckiness, in the 

 common red cedar (Jumpcrus virginiana) and in the southern red 

 cedar (Junipcnts barbadctisis), as well as in other conifers. - 



Polyporus Juniperinus von Sehrenk is apparently the cause of 

 the white rot of the red cedar.- 



Polyporus Schweinitzii Fr. is abundant in Kurope on the Scotch 

 pine, \\Vymouth pine, and the larch. 3 This species is yellowish 



1 Atkinson, Geol F. Cornell AR!'. Kxp. Sta. I'.ullt. 193 : 202-208. 1901. 

 brenk, H.von. Div. Vcg. 1'hys. and Path., r. S. Di-pt. A. u l. Iiullt.21 



pis. I-J. 1900. 



Sehrenk, II. von. Div. Vc-. 1'liys. and Path.. T. S. Dcpt. Agl. Built. 25 : 18-24. 



