American Yellow Fly Agaric

American Yellow Fly Agaric is a large, conspicuous, yellow variety of one of the most recognizable mushrooms in the world. It occurs in the United States from Maine to Maryland, west to Minnesota and Indiana, and south along the Appalachian Mountains to North Carolina. It also occurs across southern Canada from Nova Scotia to Alberta. It is not uncommon in Minnesota. It occurs in coniferous, deciduous, or mixed woodlands, woodland edges, and among planted trees. It is found from June to November, solitary, scattered, in groups, or in fairy rings, on the ground under pine, spruce, fir, aspen, or birch trees. It is mycorrhizal, obtaining its nutrients from the rootlets of a tree while facilitating greater absorption of nutrients from the soil by the tree.

When it first appears the fruiting body is egg-shaped, completely enclosed in a protective membrane (universal veil). As the mushroom expands the universal veil breaks, forming 2 to 4 concentric rings of scales at the base of the stalk. Another protective membrane (partial veil) extends from the margin of the cap to the stalk and covers the gills. At maturity, the partial veil breaks away leaving a persistent ring or collar of tissue at the middle or near the top of the stalk. The ring is fragile, whitish, often with a yellowish edge, and sometimes the edges appear torn or toothed.

The cap on young mushrooms is nearly round at first, becoming convex then ultimately nearly flat at maturity. The mature cap is is 2″ to 12″ in diameter, sometimes larger. The upper surface is hairless, slimy when moist, pale yellow, bright yellow, or orangish-yellow, often with a reddish-orange or yellowish-orange center. Occasionally, the cap is entirely orange. It is densely covered at first with cottony, wart-like fragments of the universal veil. As the mushroom ages, the warts are worn away or washed away by rain.

The stalk is 2″ to 8″ tall, sometimes taller, and ⅜″ to 13 ⁄16″ thick, sometimes thicker. It may be tapered from the base or have an expanded, bulb-like base up to 2⅜″ in diameter. It is usually scaly below the ring.

The gills are white, broad, and closely spaced. They are narrowly attached or not attached to the stalk.

The spore print is white.

The flesh is white. It is poisonous. It does not change color when cut.

Most guidebooks and authorities state that American Yellow Fly Agaric is poisonous, and it is true that about 90% of mushroom-related fatalities involve Amanitas. Fly agaric contains the hallucinogenic compounds muscimole and ibotenic acid. They may have been involved in prehistoric rituals. It is poisonous in large, possibly even in moderate amounts, but not normally fatal.

Frost’s Amanita (Amanita frostiana) is smaller, no more than 4″ in diameter and usually 3″ in diameter or less. The stem does not have concentric rings of scales near the base.

Solitary, scattered, in groups, or in fairy rings. Coniferous, deciduous, or mixed woodlands, woodland edges, and planted trees. On the ground under pine, spruce, fir, aspen, or birch.

June to November

Sources

4, 7, 24, 26, 29, 30, 77.

Widespread in North America. Common in northeastern United States.

Some authorities, including RogersMushrooms.com and the usually reliable Mushrooms Demystified by David Arora, list this as Amanita muscaria var. formosa. However, that name refers to a European variety that does not occur in North America. The North American var. guessowii was first described in 1933.

So many amanitas this fall! I've seen many clusters in the woods.

In my backyard

Beautiful mushrooms by the edge of a playground!

Some are dinner plate size here!!

found a bunch of these was hoping they were edible but wasn't sure so didn't eat.

Just after a rainfall, so I believe that the “warts” were partially washed away.

Here are some nice specimens of the Eastern yellow/orange fly agaric mushroom I found growing in the northern part of Washington county, MN near Scandia. There were hundreds of colonies on this private 14 acre plot of land.

Fairy ring

Young mushroom

Mature mushroom

Cap

Cap with warts mostly washed away by rain

Stem

Stem

Amanita muscaria var. formosa (guessowii)
"Teh Internet Tubes"

American Yellow Fly Agaric 01
Sep 27, 2020

Amanita muscaria var.formosa
MyGeorgiaFungi

Mushrooms are Gods (Part II)
Save Bigfoot

John Clark
5/24/2024

Location: Moscow Mills, Missouri 63362

Beautiful

Location: Menagha, MN

Location: Fairview Twp., Cass County

Location: St. Cloud, MN (Benton County)

Location: Isanti County

In my backyard

Location: 2003 W Willard St, Stillwater, MN 55082

Beautiful mushrooms by the edge of a playground!

Location: Battle Creek Dog Park, Ramsey County MN

Some are dinner plate size here!!

Location: St. Louis County

Location: Cass County

So many amanitas this fall! I've seen many clusters in the woods.

Location: Fairview Twp, Cass County

Location: Sartell, Minnesota

Location: Central NH, USA

Location: Barnum Minnesota 45 minutes south of Duluth

found a bunch of these was hoping they were edible but wasn't sure so didn't eat.

Location: Mankato

Just after a rainfall, so I believe that the “warts” were partially washed away.

Location: Vancouver WA

Location: Park Rapids

Location: Stearns County

Location: Washington County, MN near Scandia

Here are some nice specimens of the Eastern yellow/orange fly agaric mushroom I found growing in the northern part of Washington county, MN near Scandia. There were hundreds of colonies on this private 14 acre plot of land.

Location: Fairview Twp, Cass County

Location: Town of Lockport, New York

Location: Lebanon Hills Regional Park

Location: Fairview Twp, Cass County