This Amanita with its bright yellow to orange colored cap resembles its cousin, Amanita muscaria var. formosa. One major difference is the yellow colored remnants of the universal veil that dot the cap as opposed to the white remnants that dot the cap of Amanita muscaria var. formosa. A. flavoconia is a smaller mushroom than A muscaria var. formosa. For several years, I misidentified this mushroom as the fly agaric.
The yellow to orange, convex to flat caps range from 1 to 3 inches (2.5 to 7.5 cm) across. The edge of the cap does not have radial grooves. The stem has a skirt-like ring left by the partial veil. The stem ends in a bulb. Sometimes the lower end of the stem has yellow remnants of the universal veil. The free or slightly attached, white to yellowish gills are close and broad. The white to pale yellow stems range from 2 to 4 inches (5 to 10 cm) tall and ¼ to ½ inches (5 to 15 mm) wide. The spore print is white. Amanita flavoconia grows on the ground in oak woods, birch woods and sometimes with conifers. The season is July through October.
Yellow patches are not recommended for eating. The edibility is not well established.
There are a number of look-alikes. The closest is the somewhat rare Amanita frostiana which has radial grooves on the edge of the yellow cap and which has a collared bulb like A. muscaria.