Community find

American yellow fly agaric

Amanita muscaria var. guessowii

Group

gilled mushroom

Spore print

White

Size

Cap 5-18 cm diameter; stipe 6-15 cm long and 1-3 cm thick.

Season

Typically fruits from late summer through late autumn.

Habitat

Mycorrhizal association with deciduous and coniferous trees, often found near oak, pine, and birch in lawns, parks, and forests.

Distribution

Clade predominantly found in Northeastern North America and parts of the Midwest.

Key characteristics

Bright yellow to orange cap covered with pale yellow to white warts. White gills, white stipe with a ring, and a bulbous base featuring concentric rings of universal veil tissue.

Fruiting body

Cap is initially globose, becoming convex to flat, surface is sticky when moist. Gills are free from the stipe, close, and white. Stipe is cylindrical, white to pale yellow, with a persistent skirt-like ring and a basal bulb with scaly ridges.

How to recognise it

Look for a yellow-orange cap with yellow warts, a white stem with an apical ring, and a bulbous base with 2-4 distinct rings of tissue above the bulb.

Look-alikes

Amanita frostiana (smaller, different volva structure), Amanita flavoconia (yellow warts, different base), and Amanita wellsii (velvety orange-yellow cap).

Ecological role

Mycorrhizal fungus that forms a symbiotic relationship with tree roots, aiding in nutrient and water absorption.

Notes

This variety is a North American relative of the iconic red Amanita muscaria. The DNA of this variety shows it is distinct from the European red fly agaric, despite similar physical features besides color. It is often used in scientific studies of fungal genetics and symbiosis.