White Mushrooms in Yard: Identify the Big White Ones

Large white mushrooms on American lawns fall into a small number of groups, and one of them is the reason this page exists.

• Green-spored parasol, Chlorophyllum molybdites. A big pale cap with brownish scales, free gills that start white and turn dull green, a ring on the stem, and a green spore print. It is described as one of the most common lawn and pasture mushrooms in the country except in the Pacific Northwest, and as the most frequently eaten poisonous mushroom in North America.
• Meadow mushroom, Agaricus campestris. White cap, pink gills darkening to chocolate brown, dark brown spore print. UC IPM lists it among the fungi that fruit in turf.
• Shaggy mane, Coprinus comatus. Tall, cylindrical, covered in shaggy white scales, with a cap that dissolves into black ink from the rim inward.
• Amanita, including the destroying angels. Pure white cap, white free gills, a ring on the stem, and a cup-like volva at the base sitting below soil level.

The practical rule: if the gills are white and stay white, dig the base out and look for a volva before doing anything else.

This is the species most likely to be behind a search for a big white mushroom on a lawn, and the one most likely to send someone to hospital.

It is a large parasol-type mushroom: pale cap with brownish scales that concentrate at the centre, gills free of the stem, and a movable ring. It grows on lawns and in pastures, alone, in troops and in fairy rings, and it fruits after summer and autumn rain.

The features that separate it from the parasols people mean to pick:

• Gill colour with age. White at first, then dull greenish or grey-green. Shaggy parasols keep whitish gills.
• Spore print. Green. It is described as the only large mushroom producing a green spore print.
• Reaction. Reported symptoms are predominantly gastrointestinal — vomiting, diarrhoea and colic, often severe — beginning one to three hours after eating. Cases have been severe, particularly in children, and deaths have occurred, though Wikipedia describes them as incredibly rare.

A young specimen with gills still white is exactly where mistakes happen, which is why the spore print matters more than the gill colour on the day. The dedicated page is Chlorophyllum molybdites.

Destroying angels and death caps are white or pale, grow from the ground near trees, and contain amatoxins that destroy liver tissue. They are not confined to forests. Amanita phalloides was introduced to central California in the 1930s, is thought to have arrived on the roots of an imported cork oak, and in California associates almost exclusively with oaks — including the ornamental and landscape oaks that stand in and beside lawns. Poison Control puts it plainly: the most toxic mushrooms may be growing in your own yard, and a few bites can cause fatal liver damage.

The features to check, in order:

• Volva. A membranous cup or sac at the very bottom of the stem, usually below the soil surface. Dig, do not pull.
• Free white gills that do not change colour.
• White spore print.
• A ring on the upper stem, often skirt-like.

Delay is the danger. Amatoxin poisoning typically produces no symptoms for hours, then violent gastrointestinal illness, then an apparent recovery before liver failure. Anyone who has eaten a white lawn mushroom needs Poison Control on the phone the same hour, not the next day. See Amanita bisporigera and Amanita phalloides.

If a white mushroom in your lawn is taller than it is wide, shaped like a closed umbrella or a lawyer's wig, and the bottom edge of the cap is going grey and then black and liquid, it is a shaggy mane, Coprinus comatus.

The Missouri Department of Conservation records the cap as cylindrical becoming bell-shaped, white with flat white scales that brown with age, 1 to 2½ inches wide and 1½ to 6 inches high, on a stalk 1½ to 8 inches long and ¼ to ¾ inch wide, slightly bulbous at the base. Gills are very crowded and free, white turning black and inky from the margin inward. It fruits September to October, often in large numbers along roadsides, lawns and disturbed ground.

The dissolving is called deliquescence: the mushroom digests its own cap into black liquid to release spores. Its relative the common ink cap, Coprinopsis atramentaria, does the same thing but has a smoother grey cap without the shaggy scales, and contains coprine, a compound that blocks the enzyme which clears acetaldehyde after drinking alcohol, producing flushing, nausea, vomiting and a racing heart.

Black lawn mushrooms are covered in more detail on black mushrooms in yard.

• Assume toxic. Poison Control's guidance is that only experts in mushroom identification can separate poisonous from harmless species, and that eating any amount of any wild mushroom can be very dangerous.
• Record before removing. Cap from above, gills from below, whole stem with the base intact, and a spore print if you have a few hours. Photograph it with the app and it identifies it; keep your own photos regardless.
• Remove with gloves, bag, bin. Not the compost.
• If anyone ate any part of one, call 1-800-222-1222 immediately and keep a specimen in a paper bag. For a pet, call your vet or ASPCA Animal Poison Control at (888) 426-4435. Do not wait to see whether symptoms develop.

Garden beds grow a slightly different set of white mushrooms from lawns, because the food is wood chips, compost and bagged soil rather than buried roots.

• Onion-stalk parasol, Leucocoprinus cepistipes: a bell-shaped cap 3 to 9 cm, brown and densely scaly when young and white or cream when expanded, with a swollen stem base and yellow bruising when handled. Wikipedia records it on wood chips, in pots and in greenhouses, and notes it is easily confused with toxic species.
• Green-spored parasol, Chlorophyllum molybdites: Texas A&M AgriLife identifies the white mushrooms that pop up in yards after heavy rain as false parasols. Look for gills turning dull green and a green spore print.
• Anything with a cup at the base: a white Amanita. These grow from soil near trees and can appear at the edge of beds.

UC IPM explains that mushrooms in beds and new turf come from buried lumber, dead roots and other organic matter, and that frequent watering encourages them. Most garden fungi are decomposers that help the soil, so they do not harm vegetables or flowers.

You cannot tell from the colour, and white is the colour of some of the deadliest species. UC IPM says only an expert can distinguish edible from poisonous species; Texas A&M AgriLife notes people confuse false parasols with puffballs and button mushrooms. What identification depends on:

• Stem base: a sac-like cup points to an Amanita; a swollen bulb is common in Leucocoprinus.
• Gill colour: white turning green points to the green-spored parasol; pink turning chocolate brown points to Agaricus.
• Spore print: white, green or dark brown.
• What it grows from: wood chips, compost, turf or soil near a tree.

Photograph each of those and scan them with MushroomLens, to see which group it matches. Then keep children and pets away from it regardless. If anyone eats part of one, call Poison Control at 1-800-222-1222 (US).

Removing them does not get rid of the fungus. Texas A&M AgriLife says most of the organism is underground, picking will not stop new ones, and fungicides can harm beneficial soil fungi. Its plant pathologist's advice is to enjoy them as part of the landscape. In a vegetable bed there is one extra reason to pick them: so nobody harvests one by mistake along with the crop. Pick them with gloves, bin them, and let the surface dry between waterings.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Nothing on this page says a wild mushroom is safe to eat or safe to handle. If you find an error, tell us and we will correct it.