Gymnopilus penetrans (Fr. ex Fr.) Murr. syn. Flammula penetrans (Fr. ex Fr.) Quid. Geflecktblätteriger Tannenflämmling Common Rustgill. Cap 2-5cm across, bell-shaped to convex then flattened, often with a wavy margin; chrome yellow to golden then tawny and fading yellowish in age; smooth. Gills adnate, close, moderately broad; gold or yellowish white becoming tawny-spotted. Stem 40-60 x 4-7mm, sometimes enlarged toward base; yellowish; base whitish with downy hairs. Veil white, fibrous; leaves no ring. Flesh whitish. Odor none or mild. Taste bitter. Spores ellipsoid, warted 7-9 x 4-5.5µ Deposit orange-brown. Cheilocystidia present; no pileocystidia; clamp connections present. Habitat singly or in small tufts on hardwoods and conifers. Found throughout North America. Season July-October. Not edible, some species of Gymnopilus can be deadly poisonous.