The cap of M. stylobates is 3–15 mm (0.1–0.6 in) in diameter, and depending on its age may range in shape from obtusely conic to convex to bell-shaped to flattened.
The structure of the cap margin also depends on the age of the mushroom, progressing from straight or curved inward slightly, to margin flaring or curved backward.
The cap surface is smooth, although if viewed with a magnifying glass, minute spines can be seen.
As it ages, the surface becomes smooth, moist and somewhat glistening, and it shows grooves corresponding to the position of the gills underneath the cap.
The cap color is evenly pale watery gray.
The flesh is thin, pallid, and has no distinguishable odor or taste.

The gills appear closely spaced in unexpanded caps, but usually more distant in old individuals.
Between 8 and 16 gills extend from the margin to the stipe; there are additionally one or two tiers of small gills (lamellulae) that do not reach fully from the margin to the stipe.
The gills are narrow but become ventricose (swelling in the middle) and sometimes very broad in age, and are attached by a line or are very narrowly adnate.
Sometimes the gills split away from the stipe while remaining attached to each other; in this way they form a collar around the stipe.
Gills are pale gray but soon become whitish, with even edges.
The stipe is 10–60 mm (0.4–2.4 in) long, 0.5–1 mm thick, and, above the level of the flat circular disc at the base, is equal in width throughout.
The stipe is covered with fine white scattered fibrils, or is delicately pruinose (as if covered with a fine white powder), but it later becomes smooth.
Its color is bluish-gray when fresh but soon it fades to gray.
The basal disc is grooved (from gill impressions) and pruinose or covered with fine minute hairs, but soon becomes smooth.
The insubstantial fruit bodies are considered inedible.
The cap of M. stylobates is 3–15 mm (0.1–0.6 in) in diameter, and depending on its age may range in shape from obtusely conic to convex to bell-shaped to flattened. The structure of the cap margin also depends on the age of the mushroom, progressing from straight or curved inward slightly, to margin flaring or curved backward. The cap surface is smooth, although if viewed with a magnifying glass, minute spines can be seen. As it ages, the surface becomes smooth, moist and somewhat glistening, and it shows grooves corresponding to the position of the gills underneath the cap. The cap color is evenly pale watery gray. The flesh is thin, pallid, and has no distinguishable odor or taste.
The gills appear closely spaced in unexpanded caps, but usually more distant in old individuals. Between 8 and 16 gills extend from the margin to the stipe; there are additionally one or two tiers of small gills (lamellulae) that do not reach fully from the margin to the stipe. The gills are narrow but become ventricose (swelling in the middle) and sometimes very broad in age, and are attached by a line or are very narrowly adnate. Sometimes the gills split away from the stipe while remaining attached to each other; in this way they form a collar around the stipe. Gills are pale gray but soon become whitish, with even edges. The stipe is 10–60 mm (0.4–2.4 in) long, 0.5–1 mm thick, and, above the level of the flat circular disc at the base, is equal in width throughout. The stipe is covered with fine white scattered fibrils, or is delicately pruinose (as if covered with a fine white powder), but it later becomes smooth. Its color is bluish-gray when fresh but soon it fades to gray. The basal disc is grooved (from gill impressions) and pruinose or covered with fine minute hairs, but soon becomes smooth. The insubstantial fruit bodies are considered inedible.
Mycena stylobates