Armillaria sinapina
Can. J. Bot. 66(10): 2030. 1988.
Common Name: none
For description see Bérubé & Dessureault & 'California Mushrooms'.
Bérubé, J.A. & Dessureault, M. (1988). Morphological characterization of Armillaria ostoyae and Armillaria sinapina sp.nov. Canadian Journal of Botany Can. J. Bot. 66(10): 2027-2034. (PDF)
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.