Summary:
Armillaria cepistipes, a member of the Armillaria mellea group, is difficult to separate macroscopically. One North American species, designated North American Biological Species XI, is probably the same as Armillaria cepistipes Velen. Features include a hygrophanous, brown cap with dark scales at the cap center, whitish gills that are adnexed to decurrent and become spotted reddish brown, an enlarged stem base, a transient, fragile fibrillose ring that often appears double, and hardwood habitat.

Cap:
4-15cm across, hemispheric to convex when young, later flat to infundibuliform [funnel-shaped], margin when young incurved; "when moist hazelnut-brown to red-brown with a darker center and somewhat lubricous, fading when dry, hygrophanous, with concentric zones, light brown toward the margin, cream-ocher toward the center"; usually not squamose [scaly] or only with occasional fibrillose scales, center with dark brown fibrillose scales, "margin strongly translucent-striate, with fibrillose remains of the veil hanging from it in places", (Breitenbach), up to 10cm across, hygrophanous, ochraceous brown to cream, slightly yellowing then browning when touched; not very scaly except in the center, margin striate-fleecy, (Courtecuisse)

Flesh:
thin; "whitish, watery gray-brown when moist", (Breitenbach)

Gills:
adnexed and decurrent as a low extension, broad, 52-60 reaching stem, 3-6 subgills between each pair of gills; whitish with a flesh tint, spotting red-brown, edges brown-spotted; edges slightly crenate [scalloped], (Breitenbach), decurrent; white then spotted reddish, (Courtecuisse)

Stem:
4-10(15)cm x 0.5-1.5cm, "cylindric-conic, with a bulbous base, often bent"; "solid when young, hollow when old, elastic, tough", toward the top warm whitish with a fugacious [fleeting] ring zone consisting of whitish to yellowish fibrils, below the ring zone (barely visible when old) increasingly dingy cream with yellow tones, usually intensely yellow toward the base; longitudinally fibrillose, without flocci or only rarely with a few, (Breitenbach), up to 10cm long and up to 1.5cm wide, fairly slender, cylindric bulbous, pale and yellowing from the base, slightly fibrillose-fleecy, (Courtecuisse)

Veil:
ring fibrillose, fragile and transient, (Courtecuisse)

Odor:
pleasantly mushroomy (Breitenbach)

Taste:
"mild, irritating the throat after being chewed for a rather long time" (Breitenbach)

Microscopic spores:
spores 7.1-9.2 x 5.1-6.3 microns, broadly elliptic, smooth, iodine negative, colorless, with droplets; basidia 4-spored, 30-40 x 6-8 microns, clavate, with basal clamp connection; marginal cells among the basidia polymorphic, up to about 40 microns long, also cylindric to conic hyphal ends with an obtuse apex, ending near the edges of the gills, not exserted, up to 120 x 10 microns; cap cuticle of parallel hyphae 7-14 microns wide, hyphae of the cap scales 25-50 x 12-20 microns, brown-pigmented, septa without clamp connections, (Breitenbach)

Spore deposit:
light cream (Breitenbach)

Notes:
It is found in BC and WA at least (Banik), as well as in Europe.

EDIBILITY

avoid Armillarias growing on hardwood, (Breitenbach)