Common stinkhorn vs death cap: two white eggs in lengthwise section

Quick answer

Sliced top to bottom, an unopened stinkhorn egg shows a whitish folded stalk wrapped in a brownish jelly-like layer; a death cap egg shows the outline of a cap, gills and stem, with no jelly. Mature mushrooms are unmistakable: the stinkhorn becomes a spongy white stalk topped with olive-brown slime that smells of rotting meat.

Deadly lookalike

The death cap is deadly.

Unlike the common stinkhorn, the death cap (Amanita phalloides) contains amatoxins, which halt protein production in cells by binding the enzyme RNA polymerase II. The CDC describes a delay of 6 to 24 hours before vomiting and diarrhea begin, an apparent recovery 24 to 36 hours after the meal, and liver and multiorgan failure typically 3 to 5 days after it. Amatoxins are heat stable and are not inactivated by cooking. In the 2016 northern California outbreak, three of 14 patients needed liver transplants. The common stinkhorn is not known to be toxic.

If someone has eaten a wild mushroom and feels unwell, or may have eaten one of these, call poison control now: 1-800-222-1222 in the US. Do not wait for symptoms.

Side by side

The tell for each

A common stinkhorn with a white spongy stem and a dark olive slimy cap rising from pine needles — Common StinkhornPhallus impudicus

A death cap with a pale olive-green cap, a white skirt on the stem and a cup at the base, among dead leaves — Death CapAmanita phalloides

How they differ

Differences between the common stinkhorn and the death cap
Feature	Common Stinkhorn	Death Cap
Egg, sliced top to bottom	Common StinkhornA folded white stalk inside a brownish jelly-like layer.	Death CapThe outline of a cap, gills and stem, no jelly.
Egg outside	Common StinkhornWhitish to pinkish or purplish, attached by cord-like strands.	Death CapSmooth and white.
Mature form	Common StinkhornA white, hollow, spongy stalk with a pitted head of olive-brown slime.	Death CapA cap with white gills and a skirt-like ring on the stem.
Smell when mature	Common StinkhornCarrion.	Death CapFaint, becoming sickly sweet with age.
Base when mature	Common StinkhornThe egg remains as a cup (volva).	Death CapA bulb in a white, sac-like cup (volva).
Where it grows	Common StinkhornMulch, gardens, lawns and rich soil near rotting wood.	Death CapUnder oaks and planted trees.

FAQ

Common questions

What is inside a stinkhorn egg?

A whitish, folded stalk encased in a brownish gelatinous layer, with no gills.

Do both have a cup at the base?

Yes. The stinkhorn's egg remains as a cup when the stalk rises, and the death cap grows from a sac-like cup. The cup does not separate them; the inside of the egg does.

Sources

Where these facts come from

Phallus impudicus
MushroomExpert.com
Amanita phalloides
MushroomExpert.com
Amanita phalloides, death cap (Mushrooms Up!)
Beaty Biodiversity Museum, University of British Columbia
Amanita phalloides Mushroom Poisonings, Northern California, December 2016
CDC, Morbidity and Mortality Weekly Report

Keep checking

Read both pages in full

This page states what field guides record. It is not advice to eat, taste or handle anything, and a photo cannot settle edibility. If someone has eaten a wild mushroom that may be toxic, call poison control (1-800-222-1222 in the US) right away, before symptoms start: the deadliest species act hours later.

More comparisons

Two American Caesar's mushrooms with orange caps edged in yellow, standing in brown leaf litter

American Caesar's mushroom vs death cap

Deadly: Death Cap

Both grow from a white cup. Caesar's mushroom has an orange cap and yellow gills; the death cap has a greenish cap and white gills. Their eggs differ.

A round, yellowish-brown common earthball with a thick, scaly, cracked skin on the ground

Common earthball vs death cap

Toxic: Common Earthball
Deadly: Death Cap

Split top to bottom, a death cap egg shows a cap, gills and stem. An earthball is solid purple-black inside a thick, scaly rind.

A pale, club-shaped gem-studded puffball with a bumpy surface, with a smaller one beside it, in leaf litter

Death cap vs gem-studded puffball

Deadly: Death Cap

Sliced top to bottom, a puffball is pure white with no structure. A death cap egg shows a cap, gills and stem.

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