Lycoperdon perlatum

The gem-studded puffball or devil's snuff-box (Lycoperdon perlatum) is a moderate sized puffball mushroom with a round fruiting body, tapering to a wide stalk. It is off-white with a top covered in short, spiny bumps or "jewels".

When mature, they become brown and a hole in the top opens to release spores which are released in a burst when the body is compressed by rain drops, a touch, falling nuts, etc.

Description
Three features distinguish this mushroom in its edible stage from the later, mature stage, and from other mushrooms: If the inner structure is hard or contains gills or an inner stem, then it is not the gem-studded puffball, and may be poisonous&mdash;potentially even deadly.
 * The white, spiny looking exterior with "gems" or "studs" which are soft and detach when manipulated.
 * The outer shape is rounded and tapering, often inverted pear-shaped with no openings visible.
 * The inner structure is uniform, soft and pure white when the mushroom is immature and edible. Forms with mature spore-bearing tissues are are yellow to olive on the interior.

Edibility
Gem-studded puffballs are considered to be a choice edible mushroom when young and the gleba is homogeneous and white. They become inedible as they mature: the gleba becomes yellow-tinged, then finally develops into a mass of powdery olive-green spores.

The immature "buttons" or "eggs" of deadly Amanita species can be confused with puffballs. For this reason puffballs should always be sliced vertically and inspected for the developing structures of a mushroom. However, Amanitas will generally not have 'jewels' or a bumpy surface, for the most part.

Gem-studded puffball spores are ornamented with many sharp, microscopic spines and can cause severe irritation of the lung (lycoperdonosis) when deliberately inhaled (Anon. 1994; Strand 1967).