Calocybe gambosa
Description
Calocybe gambosa is an edible mushroom that grows mainly in fields, grass verges and roadsides. It is a medium to large, fleshy, cream-colored mushroom.
It appears in March in Italy, a warmer country where it is also a popular mushroom to eat, and is known there as "prugnolo", marzolino. It is also popular in Northern Spain and Southern France, in the Basque Country region and its surroundings where it appears in April. In these regions it is usually eaten sautéed with egg or with bacon.
An easy to identify mushroom with its mealy smell and the time of year it fruits.
Calocybe gambosa can usually be found in the same place every year and seems to grow quite successfully when old mushrooms that are too maggoty for the pot have been carefully placed in the right environment.
Common names: St. George's mushroom, Vårmusseron (Sweden), Maija Auzene (Austria).
Mushroom Identification
Cap
Convex, firm and white, turning more buff as it ages. It has a smooth surface and is between 5-15cm in diameter.
The edge of the cap often has one or more "dents" in it. It has a slightly inrolled margin, which remains as the mushroom ages.
Gills
White and very narrow in comparison to the cap flesh. This can be seen when sliced in half from top to bottom to form a cross-section of the mushroom.
The gills are sinuate - having a tooth-like attachment to the stem. This gives the false appearance of a narrow gutter between the stem and the gills.
Stem
Between 2 and 4 cm wide and 3 to 7 cm tall. It has a rough appearance - like wool bobbles on a well-worn jumper. There is no ring or volva. The base of the stem often bends out to one side.
Smell
Mealy, like wet flour. This is greatly reduced after cooking.
Spore Print
White.
Habitat & Ecological Role
In cropped pastures, often but not always near to the deciduous tree,s and on mown roadside verges near to hedges; occasionally in mixed woodland. Calocybe gambosa is considered by some authorities to be a mycorrhizal species, although its habit of sometimes growing in rings is more generally associated with saprophytic fungi. St George's Mushrooms are very common in chalk- and lime-rich areas, but they also appear in moderately acidic grasslands and woodlands. I have found these mushrooms most often under Hazel, Beech, Oak and Silver Birch, but occasionally they occur near conifer hedges.
Look-Alikes
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The gills are bruise red and it does not have a mealy smell. This is a highly poisonous mushroom.
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Also poisonous, has a rancid smell.
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The Miller, which has decurrent gills.
Medicinal Properties
Antibacterial activity
A dichloromethane extract of Calocybe gambosa was shown to be antibacterial towards Bacillus subtilis and Escherichia coli (Keller et al., 2002).
Blood sugar reduction
The title of the Brachvogel reference (1986) suggests that the St. George’s mushroom can reduce blood sugar levels, but I haven’t yet seen this German paper.
History
In 1753 Carl Linnaeus called this mushroom Agaricus georgii, but it was not until 1821 that it received its current specific epithet when it was described by Elias Magnus Fries, who named it Agaricus gambosus - most gilled fungi were placed in the Agaricus genus in the early days of fungal taxonomy.
St George's Mushroom was later - Classified by German mycologist Paul Kummer as Tricholoma gambosum before Dutch mycologist Marinus Anton Donk (1908 - 1972) reclassified St George's Mushroom as Calocybe gambosa.
The generic name Calocybe translates to 'pretty head' - a reference to the attractive caps of these edible mushrooms - while the specific epithet gambosa means 'club footed' and refers to the massive stem which often has a somewhat bulbous base.
Synonyms of Calocybe gambosa include Agaricus georgii L., Agaricus albellus DC., Agaricus gambosus Fr., Tricholoma gambosum (Fr.) P. Kumm., Tricholoma georgii (L.) Quél., Calocybe georgii (L.) Kühner, and Lyophyllum gambosum (Fr.) Singer.
Photo sources:
Photo 1 - Author: User:Strobilomyces (CC BY-SA 2.5)
Photo 2 - Author: User:Strobilomyces (CC BY-SA 2.5)
Photo 3 - Author: No machine-readable author provided. Japonica assumed (based on copyright claims). (Public Domain)
Photo 4 - Author: No machine-readable author provided. Japonica assumed (based on copyright claims). (Public Domain)
