How to identify Jack O'Lantern Mushroom

To correctly identify Jack O'Lantern Mushroom (Omphalotus illudens), 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.

   3-20 cm (1.2-8 inches) in diameter, convex to broadly convex, becoming flat or centrally depressed with age, often with a wavy or irregular margin. Color is bright orange to orange-yellow, sometimes with brownish tints, smooth, and dry.

2. 2

   Gills

   Attachment to stem, color, and spacing.

   Deeply decurrent (running down the stem), closely spaced, narrow, and often forked, bright orange to orange-yellow, bioluminescent in the dark.

3. 3

   Stem

   Length, shape, surface, and any ring.

   5-20 cm (2-8 inches) long, 1-3 cm (0.4-1.2 inches) thick, tapering towards the base, often curved, solid, concolorous with the cap or slightly paler, smooth, and lacking a ring.

4. 4

   Flesh

   Color, texture, and bruising reaction.

   Thick, firm, yellowish-orange, not changing color when cut or bruised.

5. 5

   Fruiting body

   Overall growth pattern.

   Large, fleshy, and typically orange to orange-yellow, growing in dense clusters on wood.

6. 6

   Habitat

   Where it grows and on what substrate.

   Saprobic, growing in dense clusters on decaying hardwood (especially oak) or buried wood, often appearing to grow terrestrially from buried roots.

Key Facts

Cap surfaces

Smooth, dry

Growth Form

Clustered, often in large groups

Spore Print

Creamy white to pale yellow

Body color

Bright orange to orange-yellow

Odor

Mild, not distinctive

Flesh bruises

No significant bruising or color change

Height

5-20 cm (2-8 inches)

Cap Diameter

3-20 cm (1.2-8 inches)

Fruit body characteristics

• Gill attachment: Decurrent
• Stem shape: Tapering towards the base, often curved
• Stem surface: Smooth
• Ring: Absent
• Stem cross-section: Solid

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