Common Name: Western Grisette
Cap: 8-18 cm broad, rounded
at first, then convex, finally plane and slightly umbonate at maturity;
surface viscid when moist; color dark brown, fading to light brown in
age, occasionally with a remnant of universal veil tissue; margin
conspicuously and deeply striate.
Gills: Adnexed to free, close white with brown edges.
Stem: 10-25 cm long, 1-3 cm
thick, equal to narrower at the apex; pallid, covered with fine brown
scales. Annulus absent. Universal veil forming a thick, membranous
sac-like volva, sometimes developing rusty stains.
Microscopic features: Spores 11.5-14.0 x 10-12 µm, smooth, nonamyloid, globose to subglobose. Spore print white.
Habit and distribution: Found commonly from mid-fall to mid-winter in mixed hardwood coniferous forest.
Comments: Amanita pachycolea
can be recognized by its large size, dark brown, deeply striate cap,
absence of a ring, and well developed thick white, membranous volva.
Its cousin, Amanita vaginata, is similar but smaller, has a cap which
is not nearly so deeply striate, and is grayish rather than brown. Both
species, however, can develop rusty stains on the volva.
Pics by MAIA