Its fruit bodies have convex to flattened orange-brown caps up to 7 cm (2+3⁄4 inches) in diameter, brown stipes, and whitish to pinkish-tan gills.

The original published description is based on collections found growing on the fallen trunk of Acer macrophyllum in Olympic National Park, Washington, in October 1993.

The cap color is reddish to brownish,[2] becoming paler towards the edge, and frequently has darker, irregularly shaped bruise spots.

The cap margin appears grooved or furrowed due to the thin flesh (measuring 0.5–1 mm thick) and the gills underneath.

The ring develops from a dense, white and cottony partial veil that becomes ragged as the cap grows, and sometimes persists as a temporary cortina.

[6] Armillaria sinapina is quite close in appearance, with smaller cap scales, and generally growing singly or in small clusters.