Poison Puffball Mushroom: How to Spot the Common Earthball

The mushroom people call the poison puffball is almost always an earthball, most often the common earthball, Scleroderma citrinum. The Missouri Department of Conservation calls it the pigskin puffball and lists it as poisonous: it can cause upset stomach, nausea and vomiting.

An earthball is not a true puffball. True puffballs, such as the giant, pear-shaped and gem-studded puffballs, are white inside while young. Earthballs have a thick rind and turn dark inside much earlier (Missouri Department of Conservation; Wikipedia). The Missouri Department of Conservation mentions about 20 similar Scleroderma species with blackish interiors, so 'poison puffball' is better read as a group name than as one species.

The genus name describes the rind: in Greek, sclera means hard and derma means skin (Wikipedia).

Use all five together. No single check is enough.

• Cut it from top to bottom. A young true puffball is uniform white inside, like a marshmallow (Missouri Department of Conservation). An earthball soon turns marbled, purplish and then black inside.
• Feel the skin. Earthball skin is thick, leathery and rind-like with coarse warts or scales (Missouri Department of Conservation). A true puffball's skin is thin.
• Press it gently. The Foraged Foodie blog describes earthballs as resisting compression like a fully inflated football, and Wikipedia notes their much firmer flesh. True puffballs give more easily.
• See how it opens. Many puffballs release spores through a single opening on top; earthballs simply crack and break up (Wikipedia).
• Dig out the base. When pulled up, earthballs often show a small network of root-like strands of mycelium (Foraged Foodie), and they grow near tree roots.

Why the colour check alone fails: the Foraged Foodie blog points out that very young earthballs can still have a whitish centre. A hard, thick-skinned ball with a pale middle is not cleared by its colour.

Yes, in three different ways.

• Earthballs. They cause gastrointestinal upset in people and animals (Wikipedia; Missouri Department of Conservation). Their spores can also irritate: Wikipedia records watering eyes, runny nose and conjunctivitis from spore exposure in some people, and the Foraged Foodie blog reports a mycologist who became ill after eating blueberries dusted with earthball spores.
• Amanita eggs. A young Amanita is a white ball before it opens, and some species carry deadly amatoxins. This is the reason every ball-shaped fungus gets cut in half. See death cap.
• Old true puffballs. Mature puffballs release large spore clouds; inhaling a lot of them is linked to a rare lung illness, covered on white ball mushroom in yard.

For dogs, the North American Mycological Association states that some Scleroderma species are lethal to dogs and pigs, though not to humans, and that the toxin is not known. An earthball in a yard where a dog chews things should be removed.

A death cap starts as a white egg wrapped in a veil, with no visible cap, gills or stem, so from the outside it can pass for a small puffball; Wikipedia lists juvenile puffballs among the death cap's look-alikes. Cut it lengthwise. An Amanita egg shows the outline of a developing mushroom: cap, gills and stem. A true puffball is plain white throughout. An earthball is firm and dark. If you see a mushroom outline, treat it as deadly and read death cap mushroom.

The common earthball lives in partnership with tree roots, so it comes up from the ground near trees: in woods, heathland and short grass (Wikipedia), and around the bases or exposed roots of oaks, maples and conifers (Foraged Foodie). The Missouri Department of Conservation records it statewide from July to October, singly or in groups, including on wood debris. Wikipedia calls it the most common earthball in the United Kingdom and gives its season there as autumn to winter.

Two more field signs:

• Small boletes growing out of it. Wikipedia notes that the common earthball can be parasitised by the bolete Pseudoboletus parasiticus. Mushrooms sprouting from a ball point to an earthball.
• A 'truffle' that is not one. Wikipedia notes that inexperienced hunters have mistaken earthballs for truffles because of the dark interior.

Call Poison Control at 1-800-222-1222 (U.S.) right away, or your local emergency number. Keep the rest of the ball, or a photo of the cut surface, for the specialist, and note the time it was eaten. For pets, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435, which charges a consultation fee. Do not wait for symptoms and do not try home remedies. This page does not give medical advice.

• The whole ball, top and side, in daylight.
• The base, dug out, with any root-like strands.
• The cut surface, sliced top to bottom through the centre.
• A note of the nearest tree and whether it grew in grass, in soil or on wood.

Photograph it with MushroomLens and the app suggests what it may be and which features to check next. No app or website can confirm that a wild mushroom is safe to eat.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Nothing on this page says a wild mushroom is safe to eat. If you find an error, tell us and we will correct it.