Agaricus bernardii: The Ultimate Mushroom Guide

About The Agaricus bernardii Mushroom

Agaricus bernardii is an edible agaric fungus in the family Agaricaceae. A short, squat mushroom, the thick stem is usually less than the diameter of the cap, which ranges from 5–15 cm (2.0–5.9 in). Found in Asia, Europe, North America, New Zealand and Australia it is a salt-tolerant species that grows in salt marshes, dunes, and coastal grassland.

The cap surface is whitish to buff, and can develop scales or warts in age. A tough-stemmed, fairly large species that features red-staining flesh, an inrolled cap margin, and a ring that sheathes the stem and flares outward at its apex.

Gills are initially pink before turning brown when the spores mature. The flesh turns reddish when it is cut or bruised.

Other names: Salt-loving Mushroom.

Agaricus bernardii Identification

1. Ecology

   Saprobic; growing alone, scattered, or gregariously in sand dunes and drainage areas near coastal and brackish waters; also in lawns and grassy areas along roadsides, especially where roads are salted for ice in the winter; summer and fall, or overwinter in warm climates; precise North American distribution uncertain, but well documented in California, Colorado, and Pennsylvania.

2. Cap

   5–15 cm; convex, becoming broadly convex; white and fairly bald when young, becoming cracked or subscaly and sometimes developing brownish or brown colors; dry; the margin strongly inrolled.

3. Gills

   Free from the stem; close or crowded; short-gills frequent; pink at first, becoming brown and then dark chocolate brown in maturity; covered with a white partial veil when in the button stage.

4. Stem

   5–9 cm long; 2.5–3.5 cm thick; more or less equal, or tapering to base when mature; bald or finely roughened; with a sheathing white ring that flares outward on its upper edge; solid and very firm; whitish to brownish, bruising reddish.

5. Flesh

   Whitish; changing to pinkish or reddish when sliced; not yellowing, even in the base of the stem.

6. Odor

   Unpleasant; reminiscent of brine.

7. Chemical Reactions

   KOH negative on cap surface.

8. Spore Print

   Dark brown.

9. Microscopic Features

   Spores: 6–8 x 5–6 µm; broadly ellipsoid; smooth; thick-walled; brown in KOH, with a pale, contrasting apiculus. Basidia 4-sterigmate. Cheilocystidia 30–50 x 5–10 µm; cylindric-flexuous to clavate, capitate, or a bit irregularly swollen toward the apex; septate; smooth; thick-walled; yellowish to brown in KOH. Pleurocystidia not found. Pileipellis a poorly defined cutis; elements 2.5–10 µm wide, smooth, hyaline to yellowish in KOH.

Agaricus bernardii Look-Alikes

1. Agaricus augustus

   Is usually somewhat larger and has a purple-brown spore print; it is a mushroom of forests and woodland edges.

2. Agaricus Benesii

   Has flesh that stains reddish when cut. It differs in that the surface of the cap turns pinkish-red when bruised, the lower part of the stem has whitish scales rather than being smooth, it grows with conifers and lacks a briny taste or odor.

3. Agaricus bitorquis

   Has a similar appearance, but can be distinguished by its double ring, and the lack of a fishy or briny odor. Additionally, A. bitorquis does not stain reddish when cut, and usually does not have a scaly or warty cap.

Agaricus bernardii Taxonomy & Etymology

Described and given the scientific name Agaricus bernardi by Lucien Quélet (often written as Quelet without the accent) in 1878, the Salty Mushroom looks similar to several other species, but its reddening flesh (when cut) is at least some help towards identification. The currently-accepted scientific name Agaricus bernardii dates from an 1878 publication by Lucien Quélet.

Synonyms of Agaricus bernardii include Psalliota bernardi, Fungus bernardii, Kuntze and Agaricus campestris subsp. Bernardii, Konrad & Maubl.

The specific epithet bernardii is a reference to G. Bernard, the finder of the collection from La Rochelle, France, that was used by Lucien Quélet in producing his original description of this species as Psaliota bernardii.