SPORE-DISCHARGE FROM POLYPOREAE 115 



(8.30 P.M. to 8.30 A.M.). Evidently here, as in other Polyporeae 





FIG. 40. Fomes igniarius on a trunk of Populus tremuloides. 

 Three fruit-bodies, each several years old, formed 

 where lateral branches broke away and left stubs. 

 Photographed by C. J. Humphrey in the State of 

 Wisconsin. Courtesy of the United States Department 

 of Agriculture. About J natural size. 



and the Hymenomycetes generally, the production and liberation 

 of spores from mature fruit-bodies is not affected by light. 



