Amanita jacksonii
Amanita jacksonii, also known as Jackson's slender amanita, American slender Caesar, and eastern Caesar's amanita, is a North American species of fungus in the family Amanitaceae. It is a reddish-orange colored mushroom species which can be identified by its yellow gills, large, white, sacklike volva.
History
It was given its current name in 1984 by Canadian mycologist René Pomerleau. The species was named in honor of Canadian watercolorist and mycological illustrator Henry A. C. Jackson. Both Pomerleau and Jackson were primarily active in Quebec, and first described the species from specimens found in that province.Description
The cap of the mushroom is wide; oval at first, becoming convex, typically with a central bump; sticky; brilliant red or orange, fading to yellow on the margin; typically without warts or patches; the margin lined for about 40–50% of the cap's radius. The red pigment fades from margin toward the center with age. The gills are moderately crowded to crowded, orange-yellow to yellow-orange to yellow. They are free from the stem or slightly attached to it; yellow to orange-yellow; crowded; not bruising. The short gills are subtruncate to truncate.The stipe measures, is yellow and decorated with orange fibrils and patches that are the remnants of a felted extension of the limbus internus of the otherwise white volva. The spores measure 7.8–9.8 × 5.8–7.5 μm and are broadly ellipsoid to ellipsoid and inamyloid. Clamps are common at bases of basidia. The flesh looks whitish to pale yellow and does not stain on exposure.