Agaricus albolutescens

Description

Agaricus albolutescens is an edible mushroom that is found under Oak and Monterrey Cypress. It is a moderate-sized, stocky-statured mushroom with a pleasant odor; it bruises slowly but persistently yellow. This character distinguishes it from other Agaricus species, such as Agaricus xanthodermus, a mildly toxic species which has a phenolic or medicinal odor, and bruises fleetingly yellow. Field marks of Agaricus albolutescens include a tendency to discolor tawny-brown, rather than merely yellow, and chocolate-brown free gills.

It has a strong odor of almonds. In Oakland, it has been found in Joaquin Miller park.

Agaricus albolutescens is a synonym.

Common names: Amber-staining Agaricus.

Mushroom Identification

1. Cap

   7-18 cm broad, convex to broadly convex or plane; surface usually dry, smooth or fibrillose, at first white but quickly staining amber to yellow-orange when bruised and often entirely yellowish to yellow-orange to amber or ochraceous in age; margin often huge with veil remnants.

2. Flesh

   Thick, white, usually bruising yellowish if crushed; odor strongly sweet and aniselike or almondy.

3. Gills

   Free at maturity, close, pallid, becoming grayish or grayish-pink, then eventually chocolate-brown or darker; often bruising yellow when immature.

4. Stem

   5-14 cm long, 1.5-3 cm thick, usually enlarged below (up to 5 cm thick), firm, white, or discoloring yellowish, smooth above the ring, smooth or slightly cottony-scaly below; flesh in the base not usually bruising bright yellow, but exterior of base may.

5. Veil

   Membranous, white or yellow-stained, with patches on the underside that sometimes form a cogwheel pattern; rupturing to form an ample, superior, skirt-like ring on stalk.

6. Spores

   6.0-7.5 x 4.0-5.0 µm, elliptical, and inequilateral in profile. In addition, they are smooth, moderately thick-walled, and have an inconspicuous hilar appendage. Their germ pore is absent.

7. Similar Species

   Agaricus silvicola is very similar but has a less dramatic bruising reaction, more yellowish than tawny, a normal rather than stocky stature, and slightly smaller spores. A. albolutescens and A. silvicola represent a single polymorphic species or a species complex.

Photo sources:

Photo 1 - Author: Alan Rockefeller (CC BY-SA 4.0)

Photo 2 - Author: Ron Pastorino (Ronpast) (CC BY-SA 3.0)