1917] 
BURT—-MERULIUS IN NORTH AMERICA 355 
its color, much smaller folds, and small spores. M. wmbrinus 
is much thicker than M. montanus and distinctly porose with 
pores 1 mm. deep and in diameter. 
Specimens examined: 
Idaho: Priest River, J. R. Weir, 8006, type (in Mo. Bot. Gard. 
Herb., 54914), and 12122 (in Lloyd Herb.). 
37. М. umbrinus Fries, Elenchus Fung. 1: 61. 1828; Ерісг. 
503. 1838; Hym. Eur. 594. 1874; басс. Syll. Fung. 6: 420. 1888. 
Fructification resupinate, effused, membranaceous, soft, de- 
terminate, naked at Ше ference and revolute; 
hymenium drying sepia to Chaetura-drab, 
with folds continuous, gyrose-porose, with Oo 
pores about 1-1 mm. in diameter and of about QO 
the same depth; in structure 500-1500 y thick, Fig. 35 
composed throughout of hyaline, thin-walled, М. umbrinus. 
nodose-septate hyphae 2-3 y in diameter, aad f. 8. 
somewhat longitudinally arranged and inter- 
woven but neither densely nor loosely; no cystidia; spores 
olive-buff under Ше microscope, even, 43-63-34 p. 
Fructifications 24-6 cm. in diameter. 
On rotting wood in cellar and damp places. Maine and 
Pennsylvania. November. 
In the small specimens of this species which have been 
available for study, thick-walled, colored hyphae are not pres- 
ent anywhere in the sectional preparations. If these fructi- 
fications were wholly removed from the substratum, the ab- 
sence of colored hyphae, such as are present in related species 
having colored spores, is a noteworthy specific character for 
M. umbrinus and, taken in connection with the small spores, 
should render this species readily distinguishable. The revo- 
lute margin may not be of fundamental importance as a 
specific character of this species, but at least three of the 
dried specimens cited below have the margin somewhat thick- 
ened and curved upward. I am indebted to Bresadola for a 
European specimen determined by him as Merulius umbrinus. 
Specimens examined: 
Exsiceati: Ellis, N. Am. Fungi, 1307, under the name Me- 
