Never eat a wild mushroom identified only from a website, a book or an app. Have every find checked in person by an expert, such as a mycological society.
Identification
The giant puffball is unmistakable for its size: a smooth, white ball, often 20–40 cm across and sometimes much larger, sitting on the ground and attached by a thin cord of mycelium rather than a stem. The outer skin is thin and leathery, feeling like kid leather or suede, and it cracks and peels away as the fungus ages.
The interior, called the gleba, is the key to safe identification. In young, edible specimens it is pure white, firm and uniform throughout, with a texture like marshmallow or tofu. As the puffball matures, the gleba turns yellowish, then olive-green and finally becomes a mass of olive-brown spore powder, released when the outer skin breaks. A single large fruit body produces an enormous number of spores.
When cut vertically through the centre, an edible giant puffball shows no outline of a cap, gills or stem inside, and no dark or purplish tissue. Microscopically, the spores are round, small and slightly warted. The species was formerly known as Langermannia gigantea and Lycoperdon giganteum.
Habitat and ecology
Calvatia gigantea is a saprotroph that decomposes organic matter in nutrient-rich soils. It grows in meadows, pastures, parks, gardens, field edges and hedgerows, often near nettles, and also in open woodland margins. Fruit bodies appear from summer to autumn, singly or in rings and groups, and may return in the same place in later years.
The species is widespread in temperate regions of Europe, North America and Asia. Its huge spore production makes it a common textbook example of fungal reproduction.
Uses and importance
Young giant puffballs with white, firm flesh are eaten in many countries. The skin is usually peeled, and the flesh is cut into thick slices, fried like steaks, breaded or added to soups. It absorbs flavours well but has a mild taste of its own. Once the interior shows any yellow or olive colour, it is no longer good to eat and can cause digestive upsets.
Historically, the dry spore mass of mature puffballs was used as tinder and, in folk practice, on wounds; such uses are not recommended.
Safety and edibility
The giant puffball is edible only when young, with a pure white, uniform interior. Never eat a wild mushroom based on a website: have every specimen confirmed in person by an expert, such as a mycological society or a trained mushroom adviser. The essential rule is to cut every puffball-like fungus vertically from top to bottom. If you see the silhouette of a cap, gills or stem, it is an Amanita egg, which may be a deadly death cap (Amanita phalloides) or destroying angel; discard it. If the interior is dark, purplish-black or marbled, it may be a poisonous earthball (Scleroderma).
Avoid specimens from roadsides or sprayed fields, and cook thoroughly. Inhaling large amounts of spores from mature puffballs can irritate the lungs.
If you suspect mushroom poisoning, call your local emergency number or poison centre straight away, even before any symptoms appear, and keep the remains of the mushrooms.
Look-alikes
Young Amanita eggs, including the death cap: small, egg-shaped, enclosed in a universal veil; a vertical cut reveals the outline of the developing mushroom. Common earthball (Scleroderma citrinum): smaller, with a thick, warty, yellowish skin and a firm interior that turns purplish-black early; poisonous. Other puffballs such as Lycoperdon and Bovista: much smaller, often with spines or warts.
Around the world
Giant puffballs are found across temperate Europe, North America and Asia, often in urban parks and gardens, which makes them one of the most frequently reported wild fungi by the public. Their size and sudden appearance often lead to questions to mycological societies after summer rains.
