164 
Journal of Agricultural Research 
Vol. II, No. 2 
clearly shown in Plate IX, figure 5, where the successive stages of the 
rot in this host are illustrated. The illustrations show the cellulose 
pockets in their natural size. As in case of other wood-destroying fungi, 
the rot varies to a limited extent, according to the anatomy and chemical 
contents of the wood of the host. 
The rot produced by Fames conchatus is entirely different. Conspicuous 
cellulose pockets are never formed, but the decay is frequently charac¬ 
terized by the appearance in close union of two distinct phases of the 
decomposition, depending, as it seems, on the physical and chemical 
nature of certain parts of the wood structure. A yellowish white rot 
first appears which may remain more or less permanently alongside other 
areas, continuing in the decomposition, later breaking up in irregular 
areas when dried. 
The hard, black encrusting surface sometimes assumed by Fomes 
conchatus is never present in F. putearius. Neither does the context 
become as hard and woody. The spines, although present in consider¬ 
able number in F. putearius , are not a conspicuous character. Those of 
Fomes conchatus are much more abundant and larger. 
Type locality.—Priest River, Idaho; Kaniksu National Forest. 
Habitat.—Dead coniferous wood. 
Range.—Throughout the Northwest, most abundant in the white-pine 
zone. 
Specimens have been examined from practically all the main forest 
regions. 
Trametes setosus, n. sp.—Sporophores pileate or entirely resupinate, depending 
upon its position on the substratum. The resupinate forms have sharply defined 
sterile margins and are usually found on the underside of logs, where they may extend 
for a distance of a foot or more. The distinctly sessile pileate forms are usually free 
from each other, but may be connected by the resupinate portion, occasionally nar¬ 
rowed at the point of attachment, mostly thickened at the base, rarely applanate or 
conchate, averaging 1 by 2 by 2 cm. Surface minutely tomentose, becoming smooth 
or weathered in old specimens, zonate, rich dark brown, uneven; margin thick, of 
lighter color, entire, becoming slightly serrate in old age, slightly sterile; context fer¬ 
ruginous or fulvous, spongy to corky, slightly zonate, particularly in old specimens; 
tubes long, often filled with a grayish mycelium, 1 to 1.5 mm.; mouths small, mostly 
angular, occasionally labyrinth-like, 3 to 6 to a millimeters, edges thick, tomentose; 
spores hyaline, 4 to 5 by 3 /x. The character that distinguishes the species from all of 
its near relatives is the immense number of long dense brown setae lining the inte¬ 
rior of the tubes. In no other species known to the writer is this character so dis¬ 
tinctly pronounced. The longest spines measure 41.45 /x, the shortest about 22.16 /x, 
with an average of 30.46 /x. The nature and immense number of these setae may 
be determined by a study of Plate X, figure 11. 
The fungus shown in Plate X, figures 6 to 11, was first collected in 
the Kaniksu National Forest near Priest River, Idaho, on fallen Pinus 
monticola . This tree is the principal host, although the fungus occurs 
occasionally on the wood of other trees but always on conifers. Poly- 
porus gilvus Fr., which seems to be the nearest relative and is usually 
found on the wood of deciduous trees, has not, so far as the writer is 
aware, been collected in the West. 
Trametes setosus , on account of its abundance, causes serious damage 
to fallen merchantable timber in forest-fire areas. The chemical action 
of the mycelium on the wood is to reduce the lignin principally in the 
spring wood, leaving a cellulose ring alternating with sound autumn 
wood (PI. X, fig. 10), which causes the annual rings to separate. 
