Amanita pachycolea
Description
Amanita pachycolea is a species of agaric fungus in the family Amanitaceae. Its cap is large, brown to very dark brown, sometimes paler near the margin, and always with long striations at the margin. The gills are white with distinct gray to brown edges and develop orange-brown stains in age. The stipe is long and thick, with a white to brownish fibrillose-scaly surface. The base is surrounded by a large, thick, felty, volva, that is white at first but soon develops rust to brown or yellow colors, and in age can be entirely rust-colored. There is no ring.
It was recognized as a distinct species by mycologist Daniel Elliot Stuntz, and published in 1982 by Harry Delbert Thiers. Found in western North America, it associates with conifers in coniferous and mixed forests.
The mushroom is edible, but not recommended due to possible confusion with toxic Amanita species.
Common names: Western Grisette, Stuntz's great ringless amanita.
Mushroom Identification
Cap
The cap is 7 - 12 cm wide, convex to near campanulate when young, becoming convex to plano-convex to umbonate in age, viscid to subviscid, with a decurved margin (becoming rimose and eroded), conspicuously striate or tuberculate striate (30 - 40% of the radius). The cap is dark brown, carob brown to mummy brown on disc, and becomes paler toward the margin (brown or grayish brown). The flesh is white and 5 - 10 mm thick above the stem. The volva is usually absent or leaves only a few fibrils; it is rarely present as a solitary white to whitish patch.
Gills
The gills are adnate or decurrent by a short conspicuous hook, usually free in age, close to subdistant or occasionally crowded, white when young, unchanging or becoming tawny to orange-yellow with age, ventricose, and broad. The short gills are truncate to subtruncate, of diverse lengths, plentiful, and unevenly distributed.
Stem
The stem is 11 - 24 cm long, white to olive buff to sometimes as dark as orange-brown, cylindric or narrowing upward, dry, typically with appressed fibrils or fibrillose scaly, and exannulate. The flesh is white, stuffed, and becoming hollow in age. The very large, felted to membranous volva is up to 5 mm thick, white on the inner surface, white to off-white and developing rust-colored to brown to yellow-brown spots with age on the outer surface. The volva is up 8 cm from the stem base to the top of its highest limb and collapsing in age.
Spore Print
White.
Microscopic Features
Spores 9-14 x 9-12 µ; smooth; globose or subglobose; inamyloid. Basidia 4-spored; occasionally clamped. Pileipellis an ixocutis of hyphae 2-9 µ wide. Lamellar trama bilateral; subhymenium ramose.
Photo sources:
Photo 1 - Author: Ryane Snow (snowman) (CC BY-SA 3.0)
Photo 2 - Author: USFWS - Pacific Region (CC BY-SA 2.0)
Photo 3 - Author: Adam Bryant (ayedee) (CC BY-SA 3.0)
