v.] TRAMETES RADICIPERDA. 153 



and the filaments are dissolving and feeding upon the 

 latter (Fig. 14). In the next stage of the advancing 



Fig. 14. — Sectional view of a tracbelde of the spruce-fir, attacked by the hyphse {a, 6) 

 of zTramefes, highly magnified (after Hartig). The upper part of the tracheide 

 has its walls still sound, though already pierced by the hyph® ; the lower part (c) 

 has the walls completely delignified, and converted into cellulose, which swells up 

 and dissolves. The middle-lamella is aLo undergoing dissolution. The holes in 

 the walls have been bored by hyphae. 



destruction of the timber the black dots mostly dis- 

 appear, and the white areas get larger ; the middle- 



