Milking bonnet or Nitrous bonnet

Cap 1-2.5 cm across, conical or bell-shaped, with a noticeable bump in the center and fine radial grooves from the margin to the center (a hallmark of the genus Mycena). Color gray-brown, dark gray with an olive tint, the center darker. The cap margin is thin and fragile, often splitting in old mushrooms.

Cap 0.5-1.5 cm across, conical or bell-shaped with a sharp little bump, with radial grooves. Color gray-brown, ash-gray, darker in the center. The surface is smooth, slightly damp in rain.

Gills — whitish to pale gray, moderately distant, with noticeable cross-veins between them. Attachment to the stem notched with a small decurrent tooth. Spore print white.

Gills — grayish-white, distant. Attachment notched (adnexed). Spore print white.

Stem 4-8 cm tall, 0.1-0.2 cm thick — very thin, threadlike, fragile. Color grayish-white above, dark gray to brownish toward the base. The surface is smooth. When the stem is snapped, a drop of white, milky fluid oozes out — this is the species' main diagnostic feature. In old, dried-out mushrooms the juice may not appear, but a dry whitish trace remains.

Stem 4-7 cm tall, 0.1 cm thick — very thin, threadlike, fragile. Color grayish-white above, darker toward the base. The surface is smooth. The base often has whitish mycelium.

Flesh very thin, watery, white. Smell faint; in some forms slightly radish-like or chlorine-like. Taste mild, unremarkable.

Flesh very thin, grayish-white. Does not change color when cut. Smell faint, chlorine-bleach — the main diagnostic feature.

Faint; in some populations with a note of radish or a damp cellar. Not distinctive enough for an ID.

Faint, chlorine-bleach, with a note of household cleaner or freshly sliced cucumber. It comes out when you rub the flesh between your fingers.