Giant Puffball

The giant puffball is exactly what its name promises — a smooth, white, leathery ball the size of a football or larger, sitting on meadow and field-edge soil in late summer and autumn with no visible stem, gills, or cap. Inside, a young specimen is uniformly firm and pure white, like a fresh cheese; as it matures the interior turns yellow, then olive-brown and powdery as it fills with spores, and eventually it splits and puffs out clouds of brown dust.

Its one genuinely important safety point is a cross-section test, and it is aimed squarely at the deadly amanitas. The egg-stage 'button' of a death cap or destroying angel is also a white ball, but sliced vertically it reveals the outline of a developing capped mushroom with gills inside, whereas a true puffball is featureless white throughout. Any white ball that shows internal structure — a shadow of a cap and gills, or a yellowing or discolouring interior — is not a puffball.