Earthball

Where it grows

The common earthball fruits in late summer and autumn in mycorrhizal partnership with oak, birch, and pine, especially on poor acidic sandy soils — heaths, woodland edges, and old commons. It is one of the most common fungi of British heathland and is widespread across the temperate northern hemisphere.

How to recognise it

A hard yellow-brown ball, slightly flattened, with a tough thick skin covered in coarse pyramidal scales. Crucially, when sliced open even very young earthballs have a solid dark purple-black interior, faintly marbled with white veins — completely different from the pure white interior of a young edible puffball. There is a distinctive sharp iodine or solvent smell when cut.

Edibility & cautions

Toxic. Eating an earthball causes nausea, vomiting, and severe stomach pain, usually within an hour or two; the symptoms are rarely life-threatening but extremely unpleasant. The serious confusion is with true puffballs: any “puffball” with a thick warty rind or a dark interior is an earthball. The rule is simple — slice every spherical mushroom in half before considering it food.