Summary:
Features include 1) fan-shaped whitish hairy caps that are scattered in groups, rows, or fused clusters on hardwood, 2) tough flesh, and 3) well-spaced white gills with edges that appear split or grooved lengthwise.

Cap:
1-4cm, fan-shaped (or vase-shaped if stem central), margin usually lobed and inrolled in dry weather; white to grayish white, gray, or sometimes brownish gray when wet; dry, densely hairy, (Arora), 0.5-5cm in diameter, up to 0.2cm thick, "generally gregarious, often imbricate, effused-reflexed to laterally stipitate", margin wavy, lobed or incised; whitish to gray or gray-brown; matted-tomentose, mealy, or hirsute, (Ginns(4))

Flesh:
tough, leathery, thin; "pallid or grayish", (Arora)

Gills:
"radiating from point of attachment, well-spaced"; "white to grayish; edges appearing split or grooved lengthwise (i.e., cuplike in cross section), rolling back in dry weather", (Arora), split, brittle, waxy; pale tan; smooth, (Ginns(4))

Stem:
"absent or present only as narrowed basal point of attachment", (Arora), up to 0.7cm long and 0.3cm wide, generally round in cross-section, (Ginns(4))

Odor:
pleasant (Phillips), sourish, like Heterobasidion annosum, mild, (Breitenbach)

Taste:
pleasant (Phillips), sourish, like Heterobasidion annosum, mild, (Breitenbach)

Microscopic spores:
spores 3-4(6) x 1-1.5(3) microns, cylindric, smooth, (Arora), spores 6-8(9) x 2-2.4(2.8) microns, cylindric with broadly rounded ends in face view, adaxially flattened to slightly concave or basally bent in side view, smooth, thin-walled, inamyloid; basidia 4-spored, 20-25 x 4-6 microns, narrowly clavate, (Ginns(4)), pleurocystidia and cheilocystidia not seen; basidia with clamps, some septa in cap cuticle with clamps, (Breitenbach)

Spore deposit:
white (Arora)

Notes:
It has been found in BC, OR, WA, ID, AB, MB, NB, NL, NS, NT, ON, PE, QC, SK, AR, AL, AZ, CA, CT, DC, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NH, NY, OH, OK, PA, SC, SD, TN, TX, VA, WV, (Ginns(5)). It is also found in Europe.

EDIBILITY

too small and tough to be of value, but some natives of Madagascar sometimes chew them, (Arora)