Red-spotted Mycena

The cap varies in shape from broadly conic to convex initially, soon expanding to bell-shaped or broadly convex at maturity; when expanded the cap diameter is typically between 2 and 4 cm (3⁄4 and 1+1⁄2 in). It usually has a distinct umbo, which can be abruptly convex in some individuals and very broad and low in others. The cap margin closely approaches the stem when young, but often flares or curves upward with age. The cap surface is smooth, slimy to the touch, often opaque when young but becomes partially translucent so that the outlines of the gills underneath the cap may be seen nearly to the center, before fading. It is often somewhat wrinkled or has the radial gill grooves deepening with age. It is initially dirty blackish-brown or nearly black, becoming paler dirty brown to brownish-gray with age, and usually with reddish-brown spots. The flesh is somewhat thick under the umbo, but becomes abruptly thinner over the area of the margin (about 0.15 mm). It is cartilaginous and firm, dark or pale watery gray, changing slowly to dirty reddish-brown when cut or bruised. It has no distinguishable odor, and a taste ranging from mild to slightly farinaceous (like flour). The gills are bluntly adnate, later becoming toothed and somewhat sinuate. They are narrow, becoming moderately broad (4–5 mm), whitish to pale gray in color, soon staining with reddish spots. …

The fruit bodies of M. maculata grow in groups to clumps on the wood and debris of both coniferous and deciduous trees. The fungus is found in North America and Europe (Germany and Norway). The North American distribution ranges north from Quebec, Canada, south to Mexico. Mycena specialist Alexander H. Smith, in his 1947 monograph on the genus, called it "the most abundant Mycena on conifer wood in the Pacific Northwest." It has also been recorded as a new species in Turkey (Kahramanmaraş district) in 2006.