How to tell Fen puffball from Destroying angel

Cap 5-12 cm across, hemispherical to egg-shaped in young mushrooms, becoming convex to flat with age. Color entirely white, creamy white, slightly yellowish in the center in old specimens. Surface smooth, slightly sticky in wet weather. No scales, no warts, no veil on the mature cap (unlike the fly agaric or Caesar's mushroom).

Fruiting body 3-5 cm across, spherical to flattened-spherical, with no distinct cap or stem (like all puffballs). The outer skin is whitish to cream when young, turning brown with age. Surface smooth or with fine scales in older ones.

Gilled hymenophore — gills white, free (not attached to the stem), moderately crowded. Spore print white. As in the rest of Amanita section Phalloideae, to which this species belongs, the gills are always white and free, even in mature specimens — unlike those of Agaricus.

There's no hymenophore in the usual sense — the spores form inside the fruiting body, in the gleba. In young ones the gleba is firm white, marbled in cross-section. In mature ones it becomes powdery, dark olive-brown. Spore powder dark olive-brown.

Stem 8-15 cm tall, 1-2 cm thick, cylindrical, long, slender, with a sac-like volva at the base (a remnant of the universal veil that looks like an eggshell). Color entirely white. In the upper part — a white membranous ring; firm in young specimens, may disappear in old ones. The stem surface often has thin white flaky scales and fibers.

Stem absent or very short, threadlike — the fruiting body is attached to the substrate by a mycelial "cap".

Flesh firm, entirely white. It does not change color when cut (unlike, for example, Agaricus mushrooms, which turn pink and darken). The smell gradually becomes unpleasant, with a hint of stale potato or chlorine — hence the epithet "stinking" in its Ukrainian name. In young mushrooms the smell is still faint, so don't rely on it as the only sign.

In young ones — firm, marble-white, like cheese curd. When cut it doesn't change color. In mature ones it becomes powdery, with the characteristic dark brown spore powder. Faint mushroomy smell.

Faint and unpleasant, with a hint of old potato, chlorine or fish — especially in old specimens and when the flesh is damaged. Not diagnostic for safety: the smell develops only after some time, and a young mushroom with no distinct smell can still end up in the basket and cause fatal poisoning.

Faintly pleasant and mushroomy, with no distinctive notes.