1914] 
OVERHOLTS—THE РОГУРОВАСЕЖ OF OHIO 135 
species are closely related, however, and without the spores 
it is sometimes difficult to decide between them. "Тһе species 
differs from F. fomentarius L. ex Gill. and F. applanatus Pers. 
ex Wallr. in the unencrusted pileus, the woody context, and the 
short tubes. 
13. F. igniarius L. ex Gill. Champ. Fr. 1:687. 1878. 
Boletus igniarius L. Sp. Plant. 1176. 1753. Polyporus igni- 
arius Fries, Syst. Мус. 1:375. 1821. 
Plants perennial, sessile; pileus dimidiate, convex to some- 
what ungulate, 2.5-11 x 4-25 x 1.5-12 cm., woody, grayish 
black, or entirely black, encrusted, sometimes somewhat rimose 
in age, glabrous, concentrically suleate in older plants, margin 
rather thin, acute, usually grayish in growing specimens; 
context rusty red or rusty brown, scarcely shining, zonate, 
woody, 0.5-4 em. thick; tubes 2-5 mm. long, usually indis- 
tinetly stratified, the older layers becoming distinctly whitish 
encrusted, the mouths circular, grayish brown to dark brown, 
averaging 4-5 to a mm., the walls thick and entire; spores 
(teste Romell) hyaline, subglobose, 5-7.5x 4-7 и, often 1-guttate. 
On trunks of living deciduous trees. Not common. 
In no other species is the stuffing or encrusting of the tubes 
by à whitish substance so evident as in this and the next one. 
In F. Everhartii Elis & Gall. the tubes appear to be sometimes 
filled with a whitish mycelium but the character is scarcely 
evident except on close examination, while in F. igniarius 
and F. nigricans Fries ex Gill. in sections through the hymenium 
the whitish encrustation is plainly visible, and seems to be a 
distinguishing character. The plant is further to be distin- 
guished from F. Everhartii by the hyaline spores, and the 
thicker dissepiments. The pores are somewhat smaller, but 
in measuring them the thick dissepiments are included, so 
that the number per mm. is about the same in the two species. 
From F. fomentarius L. ex Gill. and F. applanatus Pers. ex 
Wallr. the species is separated by the more woody context, 
the thinner crust, and the much shorter tubes, as well as by 
the hyaline spores. In F. igniarius the pileus is darker in color 
and is usually much more rimose than in F. nigricans. For 
illustrations see Atkinson, Cornell Univ. Agr. Exp. Sta. Bul. 
198: f. 73-4. 
