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Small white fool's funnel mushrooms in grass
Poisonousintermediate

Fool's Funnel

Collybia rivulosa / Clitocybe rivulosa; sweating mushroom

A small, frosty-white lawn mushroom with decurrent gills that contains muscarine and grows beside fairy rings.

Photo: Jose Castro, CC BY
Compiled by Mushroom Forage Map field deskExpert review pendingContent checked
Toxicity warning

Poisonous. Muscarine causes sweating, salivation, tears, and slowed heart rate. Seek medical care after ingestion.

Season
Summer to autumn
Habitat
Lawns, pastures, and grassland, often in rings
Underside
Crowded white gills running down the stem
Spore evidence
White

Where it grows

Tracked records and known growing zone

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Squares: where people recorded it, brighter where more people did
Verified records
348
People who recorded it
233
Most records (northern hemisphere)
Oct–Dec
Records span
1999–2026

Research-grade iNaturalist records, snapshot Aug 27, 2026. The growing zone combines areas where different people have repeatedly verified it. Records show where people looked and found it, not current abundance or permission to gather.

Observation season

When field records occur

Choose a hemisphere · All recorded years; not a current forecast.

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Compare before concluding

Lookalikes to rule out

Fairy ring mushroom has well-spaced gills that barely touch the stem, and a tan cap.

The miller

caution

Clitopilus prunulus smells of meal and has pink spores.

Identification

Caps are small, flat to slightly depressed, and whitish with a frosty or chalky surface. Gills are crowded and run down the stem. It grows in grass, sometimes in rings, next to fairy ring mushrooms.

Why it matters

Muscarine poisoning begins within 15 minutes to two hours. Symptoms include heavy sweating, salivation, tears, blurred vision, and a slow heart rate. It is treatable, but serious in children and people with heart disease.

Memorable fact

Its old name, sweating mushroom, describes the main symptom it causes.

Sources

Never eat a mushroom from this page alone

Confirm identity using the whole specimen, multiple reputable sources, and a qualified local expert. Identified edible species still require appropriate preparation. Cooking does not make a poisonous mushroom safe.

Safety and poison response
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