How to identify Western Giant Puffball

To correctly identify Western Giant Puffball (Calvatia booniana), 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.

   Surface is initially white to tan, covered in thick, coarse, polygonal scales that crack as the mushroom matures.

2. 2

   Gills

   Attachment to stem, color, and spacing.

   None, as it is a gasteroid fungus.

3. 3

   Stem

   Length, shape, surface, and any ring.

   Absent or represented by a sterile, thick, root-like mycelial base.

4. 4

   Flesh

   Color, texture, and bruising reaction.

   Uniformly pure white and firm (glaebal) in youth; becomes yellowish-olive and powdery as it matures into spores.

5. 5

   Fruiting body

   Overall growth pattern.

   Large, rounded fruiting body, often reaching 15-60 cm in diameter.

6. 6

   Habitat

   Where it grows and on what substrate.

   Typically found in arid or semi-arid regions, grassy fields, sagebrush steppes, and occasionally edges of coniferous forests.

Key Facts

Cap surfaces

Thick, scaly, and cracked into polygonal patterns

Growth Form

Solitary or small groups

Spore Print

Olive-brown or yellowish-brown

Body color

White to brownish-tan

Odor

Faint, pleasant mushroom scent

Flesh bruises

Does not change color significantly

Height

10-30 cm

Cap Diameter

15-60 cm

Fruit body characteristics

• Gill attachment: None
• Stem shape: None
• Stem surface: N/A
• Ring: None
• Stem cross-section: N/A

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