Trees and Timber 



373 



Rhizina on fir, pine, larch, spruce, hemlock, Pseudotsuga, 

 chestnut; Sparassis on fir, spruce, pme, larch; and Thielavia 

 (see p. 23) on catalpa; Xylaria, see p. 53. 



DECAY OF DEAD TREES OR DEAD PARTS 



While decay of dead trees cannot be regarded strictly 

 as a condition of disease, but rather as a post-mortem 



vi.Ji.C^ 



Fig. 196. — Dry-rot fungus (Merulius lacrymans); on the right the 

 mycelium is visible as white strings. After Freeman. 



change, a word is due on account of its vast importance, 

 involving, as it does, all structural wood. The fact that 

 the railroads purchased 121,402,611 cross-ties in the year 

 1915, and larger numbers in preceding years; that the num- 

 ber of posts in use in 1910 was approximately 4,000,000,000, 



