Amanita aestivalis

Key to Gilled Mushrooms Key

This is a key to gilled mushrooms, that is, mushrooms having a definite cap with a fertile surface consisting of gills. The fruiting body usually also has a stem, although that may be lateral or absent (usually, then, the mushroom is growing from wood). You can use this key to identify mushrooms that you find.

Agaricales Order

Fruiting body containing fibers (usually in the stalk)

Amanita Genus

Fruiting body having a combination of some of the following characteristics:
Stalk growing out of a cup of cottony tissue called a volva (all white-spored mushrooms with a volva go here)
Cap with scattered patches or flakes of the same sort of tissue as the volva (see second picture), easily peeled off
Annulus (skirt-like ring on stalk)

Phalloideae Section

Annulus always present
Either volva present, sack-like and cap either white or olive brown, or
Stalk with a basal bulb and cap either greyish brown or yellow

Bulbous Phalloideae SubSection

No volva
Base of stalk bulbous
Cap brownish or yellowish

Links from Look-alikes
Lepidella Section

Annulus present
Volva absent; base of stalk swollen and rooting
Universal veil material often very powdery, or leaving very pointy remnants on the cap
Cap usually white or grey

Amanita aestivalis

Here are the characters that distinguish this species from the others in its group. For its more general characters, see higher up on the page.
If there's just a few words or a microscopic feature here, a more thorough description can be found above.

Diagnosis

Prominent, slightly rimmed basal bulb which is split vertically in several places around the edge
Cap white, with some yellowish or tan on the disk
Flesh staining brown

Microscropic Characters

Spores 7-8.5 µm, round

Comments

This mushroom was originally thought to be a variety of Amanita brunnescens, but has since been recognized as a separate species. There is, however, also a recognized A. brunnescens v. pallida (Krieger) which differs mainly in having the slightly virgate cap of Amanita brunnescens (as you can see, the spore sizes are very similar. This variety intergrades with the "original" Amanita brunnescens. These intermediate mushrooms have splotches of the brownish color on the cap, that fade out at the edges. They look a lot like what happens when you touch a drop of ink to wet paper. Whether A. brunnescens v. pallida will stay separate from Amanita aestivalis is anyone's guess. In any case, it's not a distinction that a non-professional should get real stressed about making

Glossary
Mushrooms
People
Newsletter
Events

Amanita aestivalis

Fruiting body containing fibers (usually in the stalk)

Annulus always present Either volva present, sack-like and cap either white or olive brown, or Stalk with a basal bulb and cap either greyish brown or yellow

No volva Base of stalk bulbous Cap brownish or yellowish

Annulus present Volva absent; base of stalk swollen and rooting Universal veil material often very powdery, or leaving very pointy remnants on the cap Cap usually white or grey

Amanita aestivalis

Diagnosis

Microscropic Characters

Comments

Annulus always present
Either volva present, sack-like and cap either white or olive brown, or
Stalk with a basal bulb and cap either greyish brown or yellow

No volva
Base of stalk bulbous
Cap brownish or yellowish

Annulus present
Volva absent; base of stalk swollen and rooting
Universal veil material often very powdery, or leaving very pointy remnants on the cap
Cap usually white or grey