Fly Agaric

Fly agaric is the classic red mushroom with white spots, and in late summer and fall it turns up on the forest floor around Mt. Hood. The cap is deep to bright red, sometimes fading to orange or pale yellow with age, and it is scattered with cottony warts that start out yellowish and soon turn white. Those warts are leftovers of a universal veil, a skin that wraps the whole young mushroom as it pushes out of the ground.

Fly agaric is a mycorrhizal partner of trees. Its fungal threads join the roots of conifers and hardwoods and supply them with water, phosphorus and nitrogen in exchange for sugars the trees make through photosynthesis. The mushrooms you see are only the fruiting bodies of that hidden network, which is why they appear singly, in scattered groups, or sometimes in large rings on the forest floor.

The form found in the Pacific Northwest and Rocky Mountains is usually called Amanita muscaria var. flavivolvata, for its yellowish warts, and mycologists expect the naming of this group to keep changing.

Fly agaric is poisonous, and its genus also includes deadly species, so it is a mushroom to admire and photograph and then leave where it grows.