Thiers Amanita

Photo of a Thiers amanita mushroom growing on a lawn.
Safety Concerns
Not recommended/not edible
Scientific Name
Amanita thiersii

Cap and stem large, white, sticky, and shaggy. Grows in lawns, pastures, prairies, often in fairy rings. June–August. Cap oval, becoming convex; white; texture sticky, shaggy; texture can wash away in rain. Gills broad; spacing crowded; whitish yellow; attachment free. Stalk slightly bulbous at the base; white; texture sticky, shaggy; has ring. Universal veil white, collapsing on the stalk, leaving a cottony, sticky, shaggy substance. Spore print white. Spores magnified are smooth, round to broadly elliptical.

Lookalikes: Other Amanita species. Also resembles the poisonous green-spored lepiota (Chlorophyllum molybdites), which has green spores.


Cap width: 2¾–5½ inches; stalk length: 3½–8 inches; stalk width: ⅜–1 inch.

Where To Find
image of Thiers Amanita distribution map


Grows in lawns, pastures, prairies, often in fairy rings. Previously found only in southern states, this species started appearing in the Midwest around 1990. This mushroom was named after Dr. Harry Thiers (1919–2000), a mycologist, educator, researcher, and friend of the Missouri Mycological Society. Also called Thiers lepidella.

Not edible. The edibility of the Thiers amanita has not been established. It should not be eaten because it could be mistaken for one of the deadly Amanita species.

Life Cycle

This species exists most of the time as a network of fungal cells (mycelium) in the soil, digesting and decomposing organic particles. It grows outward from a central point, forming an arc or circle. The most active parts are on the perimeter (outer edge). When it's ready to reproduce, the mycelium sends up mushrooms, which are aboveground reproductive structures. The circular "fairy ring" indicates the boundary of the mycelium. The mycelium of a mushroom can live for decades.

Many inedible and even poisonous fungi have important roles in nature, benefiting humans indirectly by keeping forests productive and healthy. They also possess strange and beautiful colors and forms.

Unlike most other amanitas, which form symbiotic connections with tree roots, this species is saprotrophic: It lives on decaying forest litter, helping nutrients to return to the soil. Both types contribute to healthy forests.

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Similar Species
About Mushrooms in Missouri

Mushrooms are a lot like plants, but they lack chlorophyll and have to take nutrients from other materials. Mushrooms are neither plants nor animals. They are in a different kingdom — the fungi. Fungi include the familiar mushroom-forming species, plus the yeasts, molds, smuts, and rusts.

Always be cautious when eating edible mushrooms. Be absolutely sure of the ID, and only eat a small amount the first time you try it to avoid a reaction..