taste. The slender stem is long by thick, cylindrical, centrally attached to the cap, and hollow. Its surface is dry, dull violet to grayish-violet over the entire length. Like the cap surface, it is initially entirely pruinose, but becomes smooth in maturity. The base of the stem is covered with sharp, straight, and stiff white hairs. The gills are narrowly attached to the stem, and distantly spaced, with between 15 and 19 gills reaching the stem. The gills are up to 1.2 mm broad, thin, and pale brownish. The gill edges are pruinose, and the same color as the gill faces. Microscopic characteristics The spores are roughly ellipsoid and measure 11–12 by 6–7 µm. They are smooth, colorless, inamyloid to weakly amyloid, and thin-walled. The basidia (spore-bearing cells) are 28–37 by 8–10 µm, club-shaped, and mostly four-spored. The cheilocystidia (cystidia on the gill edge) are club-shaped, abundant, and measure 30–45 by 8–11 µm. They form a sterile gill edge. Near their tips they have one or more short knob-like excrescences (outgrowths) that are colorless, and thin-walled. M. mustea does not have cystidia on the gill face (pleurocystidia). The hymenophoral tissue is made of hyphae that are 5–16 µm wide, cylindrical (often somewhat inflated) with thin walls, smooth, colorless, and inamyloid. The cap cuticle is made of parallel, bent-over hyphae that are 2–6 µm wide, cylindrical, and covered with scattered, warty or finger-like hyaline (translucent) thin-walled diverticulae. The layer of hyphae under the cap cuticle are parallel, hyaline or pale violet, dextrinoid (turning reddish to reddish-brown in Melzer's reagent), and contain short and inflated cells that are up to 25 µm wide. The stem cuticle is made of parallel, bent-over thin-walled hyphae that are 2–6 µm wide, cylindrical, smooth, and hyaline or pale violet. The stem tissue is made of longitudinally running, cylindrical hyphae that are 8–15 µm wide, smooth, colorless, and dextrinoid. Clamp connections are absent in all tissues. Similar species Mycena mustea is similar to the North American species M. umbrinovinosa, which is distinguished by having a vinaceous-brown to purplish-black cap, irregularly shaped cheilocystidia that are covered at their tips with long, flexuous excrescences, and clamp connections. Mycena mustea is also similar to the European species M. urania, which differs in its blackish-violet cap, broadly club-shaped cheilocystidia covered with numerous, evenly spaced warts, and clamp connections. Mycena mustea also resembles the Japanese M. fonticola, a species described concurrently with