How to identify common types of poisonous mushrooms

The white-gilled, cone-shaped, and "Guangzhou Angel of Destruction" are three types of poisonous mushrooms belonging to the genus Amanita, which are widely distributed and commonly found in Vietnam.

Amanita is a widely distributed genus of mushrooms, including Vietnam. To date, 1702 species belonging to the genus Amanita have been discovered. Around the world , almost all species of mushrooms in this genus are poisonous or highly poisonous, with only a few edible species, and even those are difficult to distinguish. This genus is responsible for 90 to 95% of deaths from poisonous mushrooms globally.

On June 24th, Ms. Nguyen Thi Thu Trang, lecturer in Microbiology, Faculty of Biology - Biotechnology, University of Science and Technology of Ho Chi Minh City, stated that the Amanita genus of fungi can be identified through its external characteristics.

In terms of color, most Amanita mushrooms are red, orange, yellow, white, gray, or moss green, belonging to the fleshy mushroom group. Some Amanita mushrooms may also have red stains when bruised or broken. However, because some mushrooms have similar colors to Amanita, it is impossible to identify this poisonous mushroom solely based on color. "Check other characteristics such as the shape of the cap, collar, scales, and bumps...", Ms. Trang said.

Amanita mushrooms have caps that resemble a wide, inverted "U." This shape is also known as an umbrella shape. Species of the genus Amanita typically have dry caps, meaning they don't appear slimy or wet like other species. Feel the cap to check if it's dry or sticky. If it's recently rained and you're unsure whether the cap is genuinely slimy or just due to the rain, leave the sample and check after 1-2 days to see if it has dried.

Many Amanita mushroom species have pale patches of color on their caps, which is what makes them stand out. These can also be brown scales or white bumps on the red caps. The bumps tend to look like small raised dots. The patches of color on the mushrooms are remnants of the outer membrane from when the mushroom was young.

Additionally, you should dig up the mushroom to examine the shape of the stem at the base. Using a pocket knife, gently dig the mushroom out of the ground. The bottom part of the stem will have a very round, cup-like shape. When digging, cut deeply around the mushroom to avoid accidentally cutting the base, as this cup-shaped stem is very delicate and easily torn.

"Not all mushrooms have a swollen, bulbous stem, so this is a distinctive feature that helps differentiate Amanita mushrooms," Ms. Trang added. This part of the mushroom also has a volva covering it, and the shape of the volva varies depending on the species.

Additionally, many Amanita mushroom species have a ring located just below the cap called a "neck." It matches the color of the stem but is still easily visible. The neck can be seen from the stem on the surface or must be dug up to be seen. The neck is called the anulus or partial hyphae, and it is part of the stem as the mushroom grows taller. This helps distinguish poisonous mushrooms like them from edible ones; for example, straw mushrooms do not have a neck.

Finally, use a pocket knife to cut the cap from the stem. Gently press the cap onto a dark piece of paper. Leave it overnight, and check if the spores on the paper are white or cream-colored. A few Amanita mushrooms are not white or pale, however, these species usually have white or cream-colored spores. This is a more reliable indicator of the species during the identification process.

According to Ms. Trang, there are three types of poisonous mushrooms belonging to the genus Amanita that are widely distributed and commonly found in Vietnam.

White-gilled poisonous mushroom (Amanita verna)

"Death mushroom" is the nickname for the poisonous white-gilled mushroom, which contains the extremely dangerous toxin amanitin. This mushroom is closely related to the deadly mushroom ( Amanita phalloides ), belonging to the genus Amanita. The poisonous white-gilled mushroom usually grows abundantly in spring or the rainy season, when the air temperature is cool and humid.

In Vietnam, this type of mushroom is distributed from the North through the provinces of the Truong Son mountain range, the Central Highlands, and the Southeast. The mushrooms grow in clusters in pine forests or deciduous forests.

Poisonous white-gilled mushroom. Photo: Mondo Funghi

This mushroom species is characterized by its typical white cap, which is smooth and glossy. When young, the cap is round and egg-shaped, expanding to a diameter of 5-10 cm when mature, and slightly slimy in humid weather. The gills and stem are both white, and the base of the stem is swollen with a pouch-like volva, turning yellow when moistened with dilute KOH solution. The flesh is soft, white, and has a particularly mild aroma. Distinguishing the poisonous white-gilled mushroom from the white button mushroom is often very difficult.

The poisonous white-gilled mushroom contains high levels of alpha-amanitin, the strongest toxin in the amatoxin group. Ingestion can cause nausea, abdominal pain, vomiting, diarrhea, followed by liver and kidney failure, and coma. Importantly, the toxin in this mushroom cannot be removed by cooking, boiling, or grilling. Even refrigeration or drying does not eliminate the toxin.

White cone-shaped poisonous mushroom ( Amanita virosa)

This mushroom is easily confused with the poisonous white-gilled mushroom ( Amanita verna) because they have quite similar shapes and colors, and both grow singly or in clusters on raised mounds of earth or in forests.

The mushroom cap is white with a smooth, glossy surface. Young caps are round and egg-shaped, covered by a white volva. As they mature, the caps often become conical, extending upwards from the volva. The gills are also white. The stem is white, with a membranous ring near the top, close to the cap. The base of the stem is bulbous and also has a volva.

White, cone-shaped poisonous mushrooms. Photo: Tehran Times

The diameter of the mature white cone-shaped poisonous mushroom is quite small compared to the white-gilled poisonous mushroom, only about 4 to 10 cm. The flesh is soft but has a rather unpleasant odor, turning bright yellow when moistened with dilute NaOH solution. The spores are white, turning green when stained with iodine. The toxin is similar to that of the aforementioned mushroom, amanitins (amatoxins), which are highly toxic and can cause dangerous liver and kidney failure.

Guangzhou-destroying angel mushroom ( Amanita exitialis)

This type of mushroom has been found to cause numerous poisoning incidents in northern regions such as Son La and Ha Giang, resulting in many deaths.

The fruiting bodies of Amanita exitialis are small to medium in size. The cap is 4-7 cm wide, convex to flattened, sometimes slightly concave at the center, smooth, white and sometimes creamy in color. The margin of the cap is unstriated and without appendages; the flesh is white. The gills are freely arranged, white to whitish, short and oblong, arranged in 2-3 steps under the cap.

All parts of Amanita exitialis turn yellow when moistened with a dilute KOH solution. The mushroom typically grows in damp, broadleaf forests.

Angel mushrooms are destroying Guangzhou. Photo: National Institute for Food Safety and Hygiene Testing.

In 2020, the National Institute for Food Safety and Hygiene Testing analyzed samples of Amanita exitialis mushrooms and detected a group of amatoxins, including alpha-amanitin, beta-amanitin, gamma-amanitin, phalloidin, and phallacidin. These toxins are not broken down in the body, are absorbed in the liver and bile, and are therefore slowly excreted in the urine.

America Italy

Source link: https://vnexpress.net/cach-nhan-dien-cac-loai-nam-doc-pho-bien-4621361.html