[Vor. 1 
136 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
14. F. nigricans Fries ex Gill. Champ. Fr., Hymen. 1: 685. 
1878. 
Polyporus nigricans Fries, Syst. Мус. 1:375. 1821. 
Plants perennial, sessile; pileus dimidiate, convex to ungu- 
late, distinctly triangular in cross-section, 5-10 x 7-13 x 2-7 
cm., woody, dull brown or becoming brownish black, not en- 
crusted, smooth or cracking somewhat in age but scarcely 
rimose, azonate or with one or two concentrie furrows, the 
margin thick, acute or obtuse, with a broad ferruginous band; 
context rusty brown, zonate, woody, 0.6-2 cm. thick; tubes 
2-7 mm. long, distinctly or indistinctly stratified, becoming dis- 
tinetly white encrusted or stuffed in the older layers, the mouths 
dark brown, circular, minute, averaging about 5 to a mm., 
the walls thick and entire; spores white, subglobose or globose, 
6.5u in diameter. 
On trunks of trees, especially on Betula. Not common. 
I have one collection of this fungus from W. A. Kellerman. 
The species has been confused with the preceding one from 
which it differs in the smoother and differently colored pileus 
and in being more decidedly triangular in cross-section. The 
best illustration is that given by Boudier (Ic. Мус. т: pl. 155). 
15 F. fomentarius L. ex Gill. Champ. Fr. 1:686. 1878. 
Boletus fomentarius L. Sp. Plant. 1176. 1753. Polyporus 
fomentarius Fries, Syst. Myc. 1:374. 1821. 
Plants perennial, sessile; pileus dimidiate, convex to strongly 
ungulate, 3.5-15 x 6-20 x 2-9 em., hard and woody, grayish to 
cinereous, brownish, or black, covered with a thick horny crust 
that appears black and shining when cut, glabrous, smooth, 
never rimose, zonate or concentrically suleate, margin thick 
and obtuse; context fulvous to ferruginous, never shining, 
punky to soft-corky, zonate, 0.3-3 cm. thick; tubes 0.5-2.5 
em. long, rather distinctly stratified, mouths grayish to cin- 
namon, averaging 3 to a mm., the walls thick and entire. 
On living deciduous trees. Not common. 
Distinguished from all of the preceding species by the punky 
or soft-corky context and the usually longer tubes. Most 
closely related to F. applanatus Pers. ex Wallr. but distinguished 
from it by the much longer pores and the hyaline spores. For 
