DETAILED ACCOUNT OF SPECIFIC PLANT DISEASES 555 



zu deren Anlage bearbeitetes Holz verwendet wurde, kann die Mog- 

 lichkeit der Verschleppung des Hausschwamms in den Wald., nicht 

 bestritten werden." To this wild form, the name of Merulius Silvester 

 has been given. The domestic form of the fungus Merulius lacry- 

 mans is an obhgate saprophyte. ' The spores fall upon the exposed end 

 of a board, beam, joist, rafter, wooden column, or flooring^ which may 

 be in contact with, or resting on, a stone foundation, brick wall, or 



Pig. 199. — Cross-section of the trunk of a living silver maple rotted by Fames 

 igniarius. (After von Schrenk, Hermann, Bull. 149, U. S. Bureau of Plant Industry, 

 pi. it, 1909.) 



earth, which is shghtly damper, if not in dry weather, then during 

 rainy, than the more protected part of the same piece of structural 

 wood. Here the spore germinates and produces a mycelium, which 

 grows inside the wood from which it abstracts the proteins necessary 

 for its growth (Figs. 88 and 89). At the same time, it dissolves the 

 coniferin and cellulose of the cell-walls, and leaves behind a brown 

 residue consisting of lignin, tannin and oxalate of lime (Fig. 88) 



