How to tell Dog stinkhorn from Common earthball

There's no separate cap. The top of the stem is pointed, orange-red and finely bumpy, and only the tip is covered in sticky, shiny dark olive slime that carries the spores. Once flies have eaten it, the tip shows bright orange.

The fruiting body is globular or flattened, 3-10 cm across, with NO distinct “stalk”: it sits right on the ground. It's yellow-brown or ochre-yellow, turning darker and browner with age. The skin is thick and hard, like a shell, and covered in coarse, raised, scaly warts. That alone sets it clearly apart from the thin-skinned edible puffballs. In mature ones the top splits into ragged pieces, exposing the spore mass.

There are no gills or pores: the spores are carried in the olive slime at the tip. There's no ordinary spore print; the spores are pale yellow in mass.

The inside (the gleba) is already dark purple-black when young, and that's the key feature that separates it from the white gleba of true puffballs. It's often shot through with white or greyish veins, giving a “marbled” look. With age it turns into a dark grey-black powdery mass. Spore print dark purple-black.

The stem is 6 to 15 cm tall and about 1 cm thick, cylindrical, hollow, spongy and pitted like expanded polystyrene, white, pale yellow or pale orange, often curved and fragile.

At the base the remains of the egg form a white sac (volva) with white mycelial cords. The young fungus looks like a white or yellowish egg 2 to 3 cm across, half buried in leaf litter.

There's no separate stem. The fruiting body is anchored to the soil by a short tuft of white rhizomorphs. Unlike true puffballs, it has no distinct “stalk-base.”

The stem walls are spongy like polystyrene, whitish to pale orange. Inside the egg, a layer of clear jelly lies under the skin.

Even in young earthballs, the flesh is dark purple-black or grey-black, sometimes with thin white veins (marbled). Once you cut it, there's no mistaking that colour: it's a sign of poison. Young edible puffballs are uniformly white inside.

The smell is unpleasant and carrion-like, but much weaker than the common stinkhorn's.

Chemical and unpleasant, sometimes with a hint of rubber or phenol, which sets it apart from the pleasant mushroomy smell of edible puffballs. Taste: do not taste it.