Mycena fuscoaurantiaca is a species of mushroom in the family Mycenaceae. First reported as a new species in 2007, the diminutive mushroom is only found in Kanagawa, Japan, where it grows on dead fallen twigs in lowland forests dominated by hornbeam carpinus and Chinese evergreen oak trees. The mushroom has a brownish-orange conical cap that has grooves extending to the center, and reaches up to in diameter. Its slender stem is colored similarly to the cap, and long—up to tall. Microscopic characteristics include the weakly amyloid spores (turning blue to black when stained with Melzer's reagent), the smooth, swollen cheilocystidia and pleurocystidia (cystidia on the gill edges and faces, respectively) with long rounded tips, the diverticulate hyphae of the cap cuticle, and the absence of clamp connections.
