MurRILL: POLYPORACEAE OF NorRTH AMERICA 111 
This plant is one of the oldest fungi known, having been used 
from very early times for keeping fire, whence the name. It is 
also abundant and widely distributed, occurring on birch, willow, 
beech, maple, oak, poplar, apple and many other deciduous trees 
in various parts of the world. Fruit-bodies observed on apple, 
willow, aspen, birch, etc., in Sweden, agree perfectly with those 
growing in the New York forests; while the variations found in 
Europe are duplicated here, even to the abundance or scarcity of 
spines in the hymenium. 
Specimens are to be found in all published exsiccati bearing 
upon this group. Among the large number of collections exam- 
ined, the following may be mentioned: New York (Underwood), 
New Hampshire (Miss Minns), Ottawa, Canada (Macoun), New 
Jersey (Ellis), Virginia (Murrill), Kansas (Bartholomew), Indiana 
(Underwood), Colorado (Earle), Labrador (Waghorne), Maine 
(Ricker), New Mexico (Earle), Finland (Karsten), Sweden (Murrill), 
Thiiringen (Underwood). 
Two forms of P igniarius are listed as distinct species in Sac- 
cardo’s Sylloge, 7. ¢., Fomes badius Berk. and Fomes nigricans 
Fries. The former was collected in Arctic North America by Dr. 
Richardson and the type is at Kew. The specimen is 5 X 6 X 
2.5 cm. and has three layers of tubes which, in the brief northern 
season, were forced to develop quickly and are therefore thinner- 
walled than in our forms. Berkeley himself doubted if the plants 
were sufficiently distinct from P. igniarius. 
Fomes nigricans Fries, on the other hand, is decidedly different 
from typical P. iguiarius, being neat and smooth and shining black, 
and rimose in two directions when old. Fries observed it on birch 
only. Persoon noticed it also frequently on old willows, and 
Underwood has collected fine specimens of the same form on 
beech in the New York mountains. While studying living plants 
on willow trees in Sweden, I found stages on the same tree con- 
necting this variety with the typical form and am convinced that 
we are not here dealing with two distinct plants but with varia- 
tions due to season, food supply, rapidity of growth, or some other 
Physiological cause yet to be determined... Specimens have been 
€xamined from Finland (Karsten, Starback), Sweden (Romell, 
Murrill), Newfoundland (Waghorne), Greenland (Rostrup), New 
