Quick facts

Common names: common earthball, pigskin poison puffball, citrine earthball

Scientific name: Scleroderma citrinum

Family: Sclerodermataceae

Fruiting season: July to November

Habitat: mossy areas in woodland, especially on sandy soil

What does common earthball look like?

A mycorrhizal fungus similar in appearance to a warty potato, the common earthball is generally rounded, with no stem and dirty yellow to brown in colour. It has a rubbery, unpleasant smell – a little like gas.

Flesh: the ‘cap’ is rounded, can be 4–12cm across and 3–6cm tall. The tough skin is dirty-yellow to ochre-brown and covered in coarse, warty scales in irregular shapes. As the fungus matures, it can turn ochre-brown or green.

The flesh inside a young earthball is whitish, sometimes with a pink-purple tinge. As it ages, the flesh becomes purple-brown to black with what looks like small white ‘veins’ running through it.

Spores: the spore mass is greyish, becoming purply-black, marbled at first by white veins and powdery when mature. The individual spores are spherical and spiked. When mature, the outer skin ruptures, creating a large, irregular opening which releases the spores which are then dispersed by wind and rain.

Stipe (stalk): it doesn’t have a stem but does have a few root-like mycelial threads which are attached to the soil.

Not to be confused with: the leopard earthball (Schleroderma aerolatum), which has much finer scales. Common earthball also resembles the edible puffball but doesn’t have an opening at the top like the puffball, is less spongy and the internal flesh is never pure white.

Credit: Johannes Hansen / Alamy Stock Photo

Where to find common earthball

The fungus is very common and widespread throughout the UK. It prefers acid soils and mossy or peaty ground on heaths and in woodland, especially on sandy soil. You are most likely to see them on compacted paths in woods and forests.

Credit: Naturepix / Alamy Stock Photo

Uses of common earthball

Common earthball may not be deadly, but it is poisonous and is responsible for lots of mushroom poisonings in the UK each year. It might be because they can be confused with common puffballs, which are edible. In the past, common earthballs were sometimes even passed off as truffles.

Did you know?

The common earthball hosts the rare parasitic bolete (Pseudoboletus parasiticus), a mushroom that grows on the common earthball and nowhere else. When it does occur, however, it can do so in abundant numbers.

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