Giant puffball

Description

The giant puffball forms some of the largest fruiting bodies among fungi: a ball or flattened ball usually 10–60 cm across, and in record cases more, resembling a ball lying on the grass. When young it is white, smooth and mealy; with time it browns and cracks. It has no cap, gills or stem.

It grows in late summer and autumn in meadows, pastures, parks and gardens on fertile soils, in Poland mainly in the north of the country. It is rare in the south.

Every fruiting body must be cut in half: a yellowish, greenish or brown interior means that the mushroom is already old and unfit to eat. The interior must never show the outline of a cap and gills (a young amanita) or be gelatinous.

Identification features

Cap

A gasteroid species: no cap; fruiting body globose or flattened, diameter 10–60 cm (according to some descriptions up to 80 cm), circumference up to 135 cm; a cord of white mycelium at the base. Exoperidium of young specimens white, mealy, then light ochre, finally leathery brown. Endoperidium white, papery, greyish-yellow and dirty brown with age. The mature peridium cracks and falls off.

Hymenophore (underside of the cap)

No gills or tubes; spores form inside the fruiting body in the gleba (spore mass).

Stem

No stem; base of the fruiting body with a subgleba (poorly developed, compact, hard to distinguish from the gleba).

Flesh

Gleba (interior) white, firm, cottony and compact in young specimens; with maturation golden-yellow, greyish-yellow, finally olive-brown and powdery. Do not taste the flesh of unidentified mushrooms.

Spore print and spores

Spores yellowish, globose to broadly ovoid, smooth or finely warted, with one lipid droplet; reddish-brown in mass. Size about 3–6 µm (descriptions give varying and unclear ranges). Young spore mass white, in older specimens olive, with an unpleasant smell.

Habitat and distribution

Ecology. Saprotroph on fertile, nitrogen-rich soils (also on acidic ones), in meadows, pastures, parks and gardens, in deciduous forests.

Distribution. North America, Europe, and also Taiwan, New Zealand, Singapore. In Poland more frequent in the north, rare in the south. In Poland formerly a strictly protected species; since 9 October 2014 removed from the list of protected fungi (now unprotected). Older descriptions list it as protected in parts of Poland and as a conservation concern in Norway.

Fruiting. Late summer and autumn (in Great Britain and North America August–October); exact months in Poland — no data.

What can it be confused with?

• Scleroderma citrinum (the common earthball; Polish: tęgoskór cytrynowy) — Poisonous. A much harder, elastic fruiting body, interior dark violet-black early, with a white net-like pattern.
• Young fruiting bodies of amanitas (Amanita), e.g. Amanita virosa — In the "egg" stage they may resemble puffballs; when cut they show the outline of a cap and gills, while a puffball has a uniform white interior without gills.
• Stinkhorns (Phallaceae, e.g. Phallus) in the "egg" stage — A gelatinous interior points to a stinkhorn; such a fruiting body must not be eaten.
• Other puffballs and earthballs — Easy to distinguish because of the giant size; according to the sources there are no similar species that large.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• One of the largest known fruiting bodies, found in 1955 in northern Bohemia (Czechia), was 46 cm tall, had a circumference of 212 cm and weighed 20.8 kg.
• A specimen weighing more than 23 kg was recorded in Thunder Bay, Ontario (Canada).
• According to Lindley's calculations the fruiting body grows at a rate of about 60 million new cells per minute, producing even several trillion spores.