Got to Tricholoma dryophilum using California Mushrooms by Desjardin, Wood & Stevens, but with Mushrooms Demystified I got lost in the Tricholomataceae.
Cluster of large, sturdy mushrooms growing out of dead pine. Cap 175 mm. Bitter, but not extremely so. Keyed to Gymnopilus junonius with California Mushrooms, Desjardin, wood & Stevens, buy to G. spectabilis group with Aurora's Mushrooms Demystified with several species possibilities.
On California bay laurel
On Powdermill Trail
About 50 in a raft. Couldn't tell if all were Western Grebes, or mixed with Clark's Grebes.