How to identify Elm Oyster Mushroom

To correctly identify Elm Oyster Mushroom (Hypsizygus ulmarius), 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.

   The cap surface is smooth and can be white to cream or light tan in color.

2. 2

   Gills

   Attachment to stem, color, and spacing.

   The gills are white, decurrent, and closely spaced.

3. 3

   Stem

   Length, shape, surface, and any ring.

   The stem is short, thick, and often eccentric or lateral.

4. 4

   Flesh

   Color, texture, and bruising reaction.

   The flesh is white and firm.

5. 5

   Fruiting body

   Overall growth pattern.

   The fruiting body of Hypsizygus ulmarius is typically 5–20 cm (2–8 in) in diameter, with a broad, convex to kidney-shaped cap.

6. 6

   Habitat

   Where it grows and on what substrate.

   It grows on dead or dying elm trees and other hardwoods.

Key Facts

Cap surfaces

Smooth

Growth Form

Clustered or solitary

Spore Print

White

Body color

White to cream or light tan

Odor

Mild and pleasant

Flesh bruises

Does not typically bruise

Height

Variable, typically short

Cap Diameter

5–20 cm (2–8 in)

Fruit body characteristics

• Gill attachment: Decurrent
• Stem shape: Short, thick, eccentric or lateral
• Stem surface: Smooth
• Ring: Absent
• Stem cross-section: Solid

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