How to identify Winter Navel

To correctly identify Winter Navel (Arrhenia rickenii), check each of these features in order. Misidentification is the most common cause of mushroom poisoning, so cross-reference multiple sources.

Step-by-step identification

1. 1

   Cap

   Shape, color, surface texture, and diameter.

   Typically 0.5-3 cm in diameter, convex to plano-depressed, often deeply umbilicate (navel-like) in the center. The margin is often wavy or lobed, and can be translucent-striate when moist. Color ranges from greyish-brown to dark brown or blackish, often paler towards the margin, and can be somewhat hygrophanous, fading when dry. The surface is smooth, sometimes finely pruinose when young.

2. 2

   Gills

   Attachment to stem, color, and spacing.

   Decurrent, moderately broad, distant to subdistant, often forked or anastomosing near the stem. Color is greyish to brownish, sometimes with a purplish tint, becoming darker with age. Spore print is white.

3. 3

   Stem

   Length, shape, surface, and any ring.

   0.5-2.5 cm long and 1-3 mm thick, central or slightly eccentric, cylindrical or slightly tapering towards the base. Color is similar to the cap, greyish-brown to blackish, often paler at the apex. The surface is smooth or finely pruinose, and the stem is solid or stuffed when young, becoming hollow with age. No ring or volva.

4. 4

   Flesh

   Color, texture, and bruising reaction.

   Thin, fragile, concolorous with the cap or slightly paler.

5. 5

   Fruiting body

   Overall growth pattern.

   Small, omphalinoid, with a depressed cap and decurrent gills.

6. 6

   Habitat

   Where it grows and on what substrate.

   Saprobic, growing gregariously or scattered on mosses, particularly species of Sphagnum, but also other mosses in damp, shaded environments. Often found in bogs, fens, wet woodlands, and heathlands.

Key Facts

Cap surfaces

Smooth, sometimes finely pruinose, hygrophanous

Growth Form

Gregarious or scattered

Spore Print

White

Body color

Greyish-brown to blackish

Odor

Indistinct

Flesh bruises

No significant bruising reaction

Height

0.5-2.5 cm

Cap Diameter

0.5-3 cm

Fruit body characteristics

• Gill attachment: Decurrent
• Stem shape: Cylindrical or slightly tapering
• Stem surface: Smooth or finely pruinose
• Ring: Absent
• Stem cross-section: Solid to hollow

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