Amanita gemmata

Description

Amanita gemmata is a poisonous mushroom of the family Amanitaceae and genus Amanita. The fruit body has a cap that is dull to the golden shade of yellow. The cap surface is sticky when moist, and characterized by white warts, which are easily detached. It is initially convex and flattens out when mature. The flesh is white and does not change color when cut. The gills are white and closely spaced. The stem is pale yellow. The partial veil that covers the young fruit body turns into the ring on the stem at maturity. It can grow either singly, scattered, or in groups. It prefers habitats like coniferous and mixed forests and alongside paths, where it fruits in summer and fall.

It is widespread in Asia, Europe, and North America, where it has been found as far south as Ixtlán de Juárez, Mexico. The species has been reported from the Dominican Republic. In South America, it is known from Chile and Colombia. In Asia, the mushroom has been collected from Iran and China.

It is a toxic mushroom, containing muscarine, also found in many species in the Clitocybe and Inocybe genera, as well as in Amanita muscaria and A. pantherina. It is often confused with various other European species. A. gemmata resembles the false death cap, tawny grisette, and panther cap mushrooms. Its cap is brighter in color than the former and more yellow than the latter two.

Common names: Jonquil Amanita, Gemmed Amanita.

Mushroom Identification

1. Cap

   3-11 cm; convex to planoconvex or flat; dull yellow, fading to nearly whitish; sticky when fresh; when young covered with white warts that are easily lost as the mushroom matures; bald; the margin often lined by maturity.

2. Gills

   Free from the stem; close or nearly distant; whitish; with frequent short-gills.

3. Stem

   4-14 cm long; 1-2 cm thick; tapering slightly to the apex; with a small basal bulb; bald or finely hairy; white; with a fragile white ring that is easily lost; with a white volva that typically clings tightly to the bulb and extends to form a free rim on the upper edge of the bulb, but may fragment into soft patches or warts at the top of the bulb.

4. Flesh

   White; unchanging when sliced.

5. Spore Print

   White.

6. Habitat

   Mycorrhizal with various hardwoods and conifers; growing alone, scattered, or gregariously; summer, fall, and winter; California and the Pacific Northwest.

Look-Alikes

1. Amanita citrina

   The cap is larger and paler with white or citrine patches. The stem has a distinct stem ring.

2. Amanita amici

   Is similar in appearance to A. gemmata but is larger.

3. Amanita orientigemmata

   A mushroom ranging from Japan to China is a look-alike, but has clamps, unlike A. gemmata. Other differences between the two species include the slightly smaller spores of A. orientigemmata, and differences in the microstructure of the cap warts.

Toxicity

This mushroom contains two types of toxins:

1. Muscimol

   Also known as agarin or pantherine is one of the principal psychoactive constituents of Amanita muscaria and related species of mushroom. Muscimol is a potent and selective orthosteric agonist for the GABAA receptors and displays sedative-hypnotic, depressant and hallucinogenic psychoactivity. This colorless or white solid is classified as an isoxazole.

2. Ibotenic acid

   Also referred to as ibotenate, is a chemical compound and psychoactive drug which occurs naturally in Amanita muscaria and related species of mushrooms.

Generally, symptoms of poisoning appear within three hours of ingestion of the mushroom as visual hallucinations, nausea, vomiting, stomach pain, diarrhea, irregular and slow heartbeat and agitation. Severe cases involving coma, convulsions, or death are extremely rare.

History

In 1838 Swedish mycologist Elias Magnus Fries described this species and named it Agaricus gemmatus.

The new name Amanita gemmata was given by Louis-Adolphe Bertillon in 1866.

The specific epithet means gemmed or jewelled.

Synonyms

1. Amanita gemmata (Fr.) Gillet 1874

2. Amanita junquillea Quél. 1876

3. Amanitopsis adnata (W.G. Sm.) Sacc. 1887

4. Amanita muscaria var. gemmata (Fr.) Quél., 1886

5. Amanitopsis gemmata (Fr.) Sacc., 1887

6. Amanita adnata (W.G. Sm.) Sacc. 1925

7. Amanita junquillea var. exannulata J.E. Lange 1935

8. Amanitaria gemmata (Fr.) E.-J. Gilbert, 1940

9. Venenarius gemmatus (Fr.) Murrill, 1948

Photo sources:

Photo 1 - Author: Scott Darbey from Canada (CC BY-SA 2.0)

Photo 2 - Author: Tanja Hindemith (CC BY-SA 3.0)

Photo 3 - Author: Dick Culbert from Gibsons, B.C., Canada (CC BY-SA 2.0)

Photo 4 - Author: Michel Langeveld (CC BY-SA 4.0)

Photo 5 - Author: Andreas Kunze (CC BY-SA 3.0)