Brown : Timber Rot 
17 
Summary 
1. Hymenochaete rtibiginosa (Schrad.) Lev. is a common 
saprophyte on decorticated chestnut about Ithaca; it is found 
more rarely on oak. 
2. The fruit bodies are annual and quite xerophytic ; spores are 
shed intermittently during moist periods for several months. 
3. Spore germination occurs best in decoctions of oak or chest- 
nut sawdust and tap water. Mycelial growth was restricted and 
clamp connections were not observed. 
4. The first evidence of decay in oak and chestnut consists in 
the formation of white spots here and there in the wood. Cavities 
lined with cellulose are formed through the partial or complete 
digestion of the elements. 
5. The tissues between the infected areas remain nearly or 
quite as sound as in normal wood. Rarely do the pockets coal- 
esce through the digestion of intervening tissue. 
6. The chemical action of the fungus consists first in the delig- 
nification of the elements attacked. This begins with the ter- 
tiary layer and continues outward. 
7. Soon after the middle lamella is attacked it is dissolved 
and the elements separate or remain loosely attached at the corners. 
8. Cellulose digestion continues after the elements become 
isolated. The thin-walled elements including pith ray cells and 
wood parenchyma are first dissolved. 
9. The pockets arising in the wood are at first lined with parti- 
ally digested elements which consist of pure cellulose. In the 
final stage the white lining entirely disappears. 
10. The decay accompanying the fungus is comparable to that 
caused by Trametes abietis Karst., on red spruce and other con- 
ifers. It has a remarkable resemblance in superficial appearance 
and method of attack to that caused by Stereum frustidosum 
(Pers.) Fr. 
11. A superficial, peripheral type of decay, in which all the 
elements are attacked but not entirely digested, usually accom- 
panies the typical decay caused by Hymenochaete rtibiginosa. The 
walls remaining are dark in color and fail to respond to the cell 
ulose reaction. 
Cornell University, Ithaca, N. Y. 
