76 THE POLYPORACEAE OF WISCONSIN. 



sisting of five layers of tubes, was 20 cm. wide, 11 cm. long and 6 cm. 

 thick; the strata averaged about 6mm. in thickness. This shows the 

 relation of the thickness of the strata to the width of the zones of 

 growth. The relation of the width of the pileus to the number of zones 

 of growth shows most clearly the difference between F. marginatus and 

 F. ungulatus. 



The young specimens of F. marginatus regularly have a red var- 

 nished appearance. The freshly growing margin and tubes often exude 

 drops of a clear colorless liquid which has a slightly subacid taste. 



No. 54 [F. ungulatus (Schaeff.) ] of Sydow's Mycotheca Germanica 

 agrees well with the above forms. Polyporus pinicola (Swartz) of El- 

 lis and Everhart's North America Fungi also agrees with our F. mar- 

 ginatus. I have also compared a full series of herbarium specimens 

 of these species from the Adirondacks with our forms and find that 

 they show the same types as do the Wisconsin forms. Boletus semio- 

 vatus Schaeff. (27, tab. 270) seems to be like a young partly resupi- 

 nate form of F. marginatus. 



I have retained the two species F. ungulatus and F. marginatus be- 

 cause the forms as found in Wisconsin seemed to be quite different in 

 color, shape, size and relative rate of growth in width and thickness. 

 They are alike, however, in general habit, substance of the pileus, pores, 

 and color of the substance and it is possible that the whole series should 

 be included in one very variable species. Murrill (19, 30, p. 328.) 

 takes this view. 



(b.) Substance rust-colored or ferruginous brown. 



Fomes salicinus Fries. 



Woody, very hard, undulate, the greater portion usually resupinate, 

 with a narrow indurated, smooth, free margin, that is obtuse and pat- 

 ent, cinnamon, then grayish; pores minute, rounded, ferruginous-cin- 

 namon, as is also the flesh ; spores 5x3 microns ; cystidia plentiful 12 

 to 35 by 6 microns. 



Comparatively common on willow. Found also on dead and living 

 trunks of oak and iron- wood. All the specimens but one are entirely 

 resupinate. The longest one was about 20 cm. long, 5 to 7 cm. wide. 

 They vary in thickness. A young unstratified specimen is about 5 mm. 

 thick. One specimen with eight strata measures about 1.4 em. in 

 thickness. The reflexed portion of the pileus is 1.5 cm. wide. 



