Mycena multiplicata is a species of mushroom in the family Mycenaceae. First described as a new species in 2007, the mushroom is known only from Kanagawa, Japan, where it grows on dead fallen twigs in lowland forests dominated by oak. The mushroom has a whitish cap that reaches up to in diameter atop a slender stem long by thick. On the underside of the cap are whitish, distantly spaced gills that are narrowly attached to the stem. Microscopic characteristics of the mushroom include the amyloid spores (turning bluish-black to black in the presence of Melzer's reagent), the pear-shaped to broadly club-shaped cheilocystidia (cystidia found on the gill edge) covered with a few to numerous, unevenly spaced, cylindrical protuberances, the lack of pleurocystidia (cystidia on the gill face), and the diverticulate hyphae in the outer layer of the cap and stem. The edibility of the mushroom is unknown. Taxonomy, naming, and classification The mushroom was first collected by Japanese mycologist Haruki Takahashi in 1999, and reported as a new species in a 2007, along with seven other Japanese Mycenas. The specific epithet is derived from the Latin word multiplicata, meaning "multiplicative". Its Japanese name is Keashi-ochiedatake (ケアシオチエダタケ). Takahashi suggests that the mushroom is best classified in the section Mycena of the genus Mycena, as defined by Dutch Mycena specialist Maas Geesteranus. Description The cap of M. multiplicata is conical to convex to bell-shaped, reaching in diameter. It is often shallowly grooved toward the margin, dry, and somewhat hygrophanous (changing color when it loses or absorbs water). The cap surface is initially pruinose (appearing as if covered with a fine white powder), but soon becomes smooth. The cap color is whitish, sometimes pale brownish at the center. The white flesh is up to 0.3 mm thick, and does not have any distinctive taste or odor. The slender stem is long by thick, cylindrical, centrally attached to the cap, and hollow. Its surface is dry, pruinose near the top, and covered with fine, soft hairs toward the base. It is whitish to grayish-violet near the top, gradually becoming dark violet below. The stem base is covered with long, fairly coarse, whitish fibrils. The gills are narrowly attached to the stem, distantly spaced (between 13 and 16 gills reach the stem), up to 1.7 mm broad, thin, and whitish, with the gill edges the same color as the gill faces. The edibility of the