Minnesota Seasons - Western Giant Puffball

Conservation • Description • Habitat • Ecology • Distribution • Taxonomy

Conservation Status

Photo by Dan W. Andree

IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

Description

Western Giant Puffball is a large to very large, prominently sculpted puffball. It occurs in arid and semi-arid regions in the United States and southern Canada from the Great Plains west to the Sierra Nevada Mountains. It is replaced in the east and on the West Coast by Giant Puffball (Calvatia gigantea). iNaturalist.org has many observations in the east, reaching all the way to the East Coast, but only a small handful of these have been verified.

Western Giant Puffball appears in summer and fall, under sagebrush and juniper, and in open areas, including meadows, forest openings, and roadsides. It is found on the ground alone, widely scattered, in groups, or in fairy rings, which can be quite large. It gets its nutrients from decayed organic matter (saprobic).

When it first appears, the fruiting body is whitish and prominently sculpted with large warts. As it matures, the warts are separated into large, buff or tan, flattened, polygonal plaques. The plaques are up to ¾″ (2 cm) thick and brownish in the center. As the puffball matures, they fall away or disintegrate, revealing the pale gray outer surface (endoperidium) below. The mature puffball is whitish to tan, buff, or brown. It is sometimes round like a ball and sometimes lobed, but it is more often flattened and blob-like. It is usually 6″ to 12″ (15 to 30 mm) wide and 2¾″ to 12″ (7 to 30 mm) high, but it can be much larger.

There is no stem. If there is a sterile base, it is rudimentary. The puffball is often attached to the ground by a small cord (rhizomorph).

The interior is the spore mass. It is white and firm at first. It turns greenish yellow as it matures, then olive brown to brown and dust-like at maturity. It is edible when firm and white without a trace of color, but it is often infested with maggots, and some people report that it has a laxative effect.

Similar Species

Giant Puffball (Calvatia gigantea) outer surface is smooth.

Habitat and Hosts

Open areas, including meadows, forest openings, and roadsides

Ecology

Season

Summer and fall

Distribution
		Sources 24, 26, 29, 30, 77. The counties in light green on the map represent unverified citizen science observations from iNaturalist.org.
10/3/2025

Occurrence
Uncommon or rare in Minnesota

Taxonomy

Kingdom

Fungi (fungi)

Subkingdom

Dikarya

Phylum

Basidiomycota (club fungi)

Subphylum

Agaricomycotina (jelly fungi, yeasts, and mushrooms)

Class

Agaricomycetes (mushrooms, bracket fungi, puffballs, and allies)

Subclass

Agaricomycetidae

Order

Agaricales (common gilled mushrooms and allies)

Suborder

Agaricineae

Family

Lycoperdaceae (puffballs)

Genus

Calvatia

Order
The family Lycoperdaceae was formerly placed in the order Lycoperdales. Recent molecular phylogenetic studies resulted in a resturcturing of fungal taxonomy. Genera formerly in the families Tulostomataceae, Battarreaceae, Lycoperdaceae, and Mycenastraceae have been moved to the suborder Agaricineae in the order Agaricales.

Family
The genus Calvatia has traditionally been placed in the family Lycoperdaceae. Recent phylogenetic analysis proposed making that family a subgroup within the family Agaricaceae. The proposal has been accepted by MycoPortal but by few others. Index Fungorum, MycoBank, Catalog of Life, Discover Life, GBIF, NCBI, and iNaturalist all include Calvatia in the family Lycoperdaceae.

Subordinate Taxa

Synonyms

Common Names

Giant Western Puffball

Western Giant Puffball

Glossary

Rhizomorph

A root-like, mycelial cord of a fungus, formed from vessel hyphae surrounding sheathing hyphae, and capable of transferring nutrients over long distances.

Saprobic

A term often used for saprotrophic fungi. Referring to fungi that obtain their nutrients from decayed organic matter.