Common earthball (Scleroderma citrinum)

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.