19141 
OVERHOLTS—THE POLYPORACEJE OF OHIO 105 
ing in a smooth layer from the context; spores (teste Murrill) 
white, cylindrical, curved, 4-5 р long. 
Growing only on Betula. Not common. 
Always easily recognized by the habitat, the smooth, pellic- 
ulose surface and the inrolled, broadly sterile margin of the pil- 
eus. Good illustrations are given by Freeman (Minn. Plant 
Diseases f. 126), Hard (Mushrooms f. 337), White (Hymen. 
Conn. pl. 37), and Kellerman (Ohio Myc. Bul. 10: f. 43). 
27. P. volvatus Peck, Rept. N. Y. State Mus. 27: 98. 1875. 
Plants annual, sessile or attached by a stem-like base; pileus 
globose or compressed-globose in form, 1-5.5 em. broad, 1- 
3.5 em. thick, somewhat coriaceous-corky when fresh, hard and 
firm when dry, somewhat encrusted, whitish or yellowish, some- 
times tinged with red, glabrous, azonate, margin thick and 
rounded, extending downward and backward and forming a veil- 
like covering over the hymenium; context white or light colored, 
soft-corky, 0.2-1 em. thick; tubes 2-5 mm. long, the mouths 
whitish to brownish, circular, averaging 3-4 to a mm.; the cover- 
ing over the hymenium ruptures in from one to three places and 
allows the escape of the spores; spores (teste Peck) flesh- 
colored, elliptical, 5 х 7.5-9 и. 
On dead wood of coniferous trees. Rare. 
An aberrant form easily recognized by the veil-like covering 
of the hymenium. This is persistent, being coriaceous in tex- 
ture and as much as 1 mm. thick. Peck’s illustration (Rept. 
N. Y. State Mus. 27. pl. 2. f. 3-6) gives some idea as to the 
general form of the plant; Hard’s (Mushrooms f. 340) is not 
much better. von Schrenk gives a good illustration (U. 5. 
Dept. Agr., Div. Veg. Path. Bul. 25: pl. 1. f. 2). 
28. P. distortus Schw. ex Fries, Elench. Fung. 1:79. 1828. 
Boletus distortus Schw. Syn. Fung. Car. 97. 1822. Poly- 
porus abortivus Peck, Bot. Gaz. 6: 274. 1881. 
Plants stipitate or substipitate, variable in form and size, 
sometimes with a distinct, well developed, centrally placed 
stipe, sometimes the whole plant distorted and the stipe rudi- 
mentary, often almost the entire surface of such forms covered 
with the tubes; pileus cireular to irregular in outline, fleshy- 
tough when fresh, firm and coriaceous when dry, variable in 
color, whitish, grayish, tan-colored, rufescent, or brownish, vil- 
