What You Should Know
Pear-shaped, yellowish brownish puffball with a pore at the top. Grows in large clusters on decaying wood from July to November. Considered an excellent edible mushroom, when young and fresh — with caution. Lycoperdon pyriforme is one of only a few puffballs that grow on wood, which makes it fairly easy to identify.
When mature, a pore opening at the top releases spores. Spore print olive brown. Spores magnified are round, smooth.
Before you pick them, cut one open to check its maturity. When young, they have a firm white flesh but if they are old, the area near the top will have turned yellowish and they will become spongey.
Other names: Stump Puffball.
Lycoperdon pyriforme Mushroom Identification
Typically 1.5 to 4cm across and 3 to 4cm tall, the pestle-shaped to pear-shaped fruitbody of the Stump Puffball is initially covered in short pyramidal warts. At first white, the skin turns brown and a dark area develops at the apex, which ultimately opens to release the spores. The fruitbody is attached to the substrate - usually the stump, half-buried rotting branches or roots of a dead tree - by means of long, white mycelial filaments extending deep into the substrate.
The short, spongy stem is usually more or less parallel or slightly conical tapering in towards a truncated base; it contains infertile material that remains white even when the gleba in the 'head' of the fungus has matured and turned dark olive-brown.
Round or subglobose, smooth, 3.5-4.5µm in diameter. Spore mass olive-brown, eventually becoming dark brown when fully mature.
Unpleasant gas-like odour; taste not distinctive.
Habitat & Ecological role
Saprobic, found growing mainly on stumps and roots of dead trees, usually hardwoods but occasionally on softwoods too. Stump Puffballs may appear to be growing on soil, but there is always rotten wood or decaying woody debris just beneath the surface. (The Stump Puffball is the only puffball species in Britain and Ireland that grows on wood rather than on soil.)
Lycoperdon pyriforme Look-Alikes
Pigskin puffball (Scleroderma citrinum) is brownish; inside it is dark brownish purple. Gem-studded puffball (L. perlatum) is white with dense spiny warts; it fruits on the ground (not on wood). Some other mushrooms, including the deadly destroying angel (Amanita bisporigera), have young "button" stages that resemble puffballs.
Make sure you cut through puffballs from top to bottom to confirm they are pure white inside, like a marshmallow, with no sign of a developing cap or stem.
Lycoperdon pyriforme Cooking Notes
The first and most important step is to remove the tough outer skin - a fiddly job perhaps best done with a sharp knife. Choose only fresh young fruit bodies which, when cut in half along the vertical axis, are white all through. Discard any that have begun turning yellow, olive or brown, as this indicates that the spores are maturing and the flavor will be seriously marred if you include them in your dish.
One of the best meals that you can make with these puffballs is a mushroom omelet; they can also be fried with onions or used to make soups.
Lycoperdon pyriforme Video
All photos were taken by the Ultimate Mushroom team and can be used for your own purposes under the Attribution-ShareAlike 4.0 International license.