Spongipellis unicolor (Fr.) Murrill 1907

Spongipellis unicolor (Schw,) Murrill
Boletus unicolor Schw. Schr. Nat. Ges. I^eipzig 1 : 97. 1822.
Sistotrema spongiosum Schw. Schr. Nat. Ges. Leipzig 1 : 101. 1822. (Type from North Carolina.)
Polyporus labyrinthicus Fries, Klench. Fung. 83. 1828.
Polyporus unicolor V ties,, Kpicr. Myc. 458. 1838.
Polyporus obtusus Berk. Ann. Mag. Nat. Hist. 3 : 390. 1839. (Type from North America.)
Polyporus Schulzeri Fries, Hymen. Hur. ed. 2. 556. 1874. (Type from Hungary.)
Polyporus iomentoso-quercinus A. K. Johnson, Bull. Mitin. Acad. Nat. Sci. 1 : 338. 1878. (Type
from Minnesota.) Trameies unicolor Murrill, Bull. Torrey Club 32 : 638. 1906. Pileus somewhat imbricate, large and spongy, at length indurate, dimidiate, sessile, often ungulate, 5-7 X 10-15 X 3-5 cm. ; surface spongy-tomentose, hirtose, azonate, smooth, sordid-white to isabelline or fulvous; margin very thick and rounded, sterile, entire, concolorous : context spongy-fibrous, white, indurate with age, especially below, 1~2 cm. thick ; tubes very long, 2-3 cm., white to isabelline within, mouths large, irregular, often sinuous, 1-2 mm. broad, edges thin, fimbriatedentate to slightly lacerate, white to isabelline, at length bay and resinous in appearance: spores globose, smooth, hyaline, 6-8/^; hyphae hyaline, 6//; cystidia none.
Type locality : North Carolina.
Habitat : Diseased living trunks of various species of oak ; also found on living maples. Distribution : New Jersey to Alabama and west to Mississippi and Minnesota ; also in Europe.

Spongipellis unicolor is a species of polypore fungus in the family Polyporaceae. It is a plant pathogen that affects oak trees. The fungal hyphae grow inside the tree, rotting the heartwood. The fruit bodies are initially whitish to buff in color before turning brownish in age. The pores on the underside of the cap are circular to angular. Spores are held in tubes and are ovoid to ellipsoid, with dimensions of 7–9 by 6–7 μm.