Distribution: Common and widespread
Habitat: On conifer and hardwood including stumps, logs, wood chips, and sawdust.
Conservation Status: Not of concern
Gymnopilus penetrans is a medium-sized typical gymnopilus. The cap of is smooth to slightly scaly and brownish orange-yellow to reddish yellow or pale red-brown, usually with a lighter edge when expanded. The gills are yellowish and often become red-spotted with age. The stipe is whitish to yellowish and typically becomes reddish brown below; often there are whitish veil fibrils on the surface. The veil is whitish to pale yellowish and usually disappears as the fruitbody develops although some specimens retain a slight fibrillose ring. The flesh is very bitter and white cords often extend from the stipe base into the substrate. Some mycologists have separated several very similar species from G. penetrans, including G. sapineus, with a scalier cap, and G. hybridus, with a fibrillose ring and spotted gills.