Marasmius plicatulus, also known as the red pinwheel or pleated marasmius, is a species of fungus.[1] According to the Fungi of California website, "This handsome Marasmius is recognized by its velvety mahogany cap, slender stature, widely spaced pallid to pinkish gills, and shiny, thin, wiry stipe."[2] The red pinwheel is often found in association with oak trees or conifers, and flushes most commonly during the winter months of November to January.[3] Of the Marasmius species found on the Pacific coast of North America, the pleated is physically the largest.[4] The red pinwheel appears to be predominantly known from western/coastal North America, although it has been observed as far inland as Idaho.