Habitat: Under conifers
Conservation Status: Not of concern
A. sinapina differs only slightly in appearance, with a cobwebby veil and slightly smaller cap scales, grows singly or in clusters of only a few individuals, and in the PNW appears to also grow primarily on conifers. Its most distinctive feature in eastern North America, the bright yellow color of its veil, is lacking, or at least inconsistent, in PNW specimens. Thus, this species often cannot be distinguished from A. ostoyae. A. ostoyae is a virulent pathogen of conifers, and, although edible when young, is considered worth collecting by relatively few mycophagists.
Sources: Trudell, Steve and Joe Ammirati. Mushrooms of the Pacific Northwest. Portland, Timber Press, Inc. 2009.
PNW Herbaria: Specimen records of Armillaria ostoyae in the Consortium of Pacific Northwest Herbaria database
CalPhotos: Armillaria ostoyae photos