It's a very good idea to be cautious around wild mushrooms. Although many species are considered quite tasty, even some edible mushrooms can cause upset stomachs in vulnerable people, especially the old and the young. Many poisonous mushrooms can cause such severe gastric distress that people who eat them require hospitalization. A few species of mushrooms can even be lethal. In fact, it is so difficult to distinguish between toxic and non-toxic varieties of mushrooms that it is considered safest not to eat wild ones at all. Only gather mushrooms that you can positively identify; if you have even the slightest uncertainty about the identity of a mushroom, don't pick it. Even with this precaution, you should always have an expert verify the safety of the mushrooms you collect.

The Worst Mushrooms

The Amanita family of mushrooms includes many different toxic species, including two that are responsible for a large number of severe illnesses and deaths each year: the Death's Cap and the Destroying Angel. A few members of the Amanita family are edible, such as the Caesar's Mushroom, which is considered a delicacy. To prevent potentially fatal mistakes, however, no mushroom that fits the description of an Amanita should be picked, or eaten, by a novice mushroom gatherer.

Characteristic Appearance

At the base of the stem is a volva, a membranous sheath of tissue that resembles a sack or bag. The cap is egg shaped when young, but flattens out as the mushroom ages. There is usually a ring or circular flap of tissue that runs around the stem beneath the cap.

Signs of Amanita Poisoning

Until approximately 24 hours after ingesting an Amanita, there are few, if any, signs that anything is wrong. After that time, a stomach upset occurs, with diarrhoea, nausea, vomiting, and cold sweats. Over time, the vomiting grows worse, until there is a serious danger of dehydration. If not cared for, people get so weak that they die due to heart failure. If this does not happen, the outward symptoms may diminish, but the poisons continue to destroy the internal organs, especially the liver and kidneys. The victim usually remains lucid until death from massive organ failure.

There is no cure for Amanita mushroom poisoning. No one has ever found an antidote for the toxins in the Amanitas, although a combination of vitamins B and C has been found to help eliminate or destroy them. Because of the potential for liver damage, hepatic protectors are often administered, including cortisone, various anti-enzymes, and silymarin (a liver-protecting drug extracted from a plant in the cardoon family).

In serious cases of poisoning, blood transfusions, dialysis, or even liver and kidney transplants are necessary to save the victims' lives. Even these extreme measures are not always successful.

Death's Cap (Amanita phalloides)

The Death's Cap mushroom is responsible for the majority of mushroom deaths; 90% of all fatal mushroom poisonings are caused by this species. Common in both North America and Europe, this mushroom poses one of the biggest risks to casual gatherers. It has a variety of appearances, so it can be difficult to properly identify. Known to contain more than twenty different toxic chemicals, the Death's Cap is not something that you want to eat; ingesting even one mushroom can be lethal.

Identifying Characteristics

The Death's Cap has a surprisingly large number of different appearances. It comes in a variety of colours, so this is not considered a reliable identifying characteristic, but it is most often olive or olive-brown in colour. It can also be pale green or yellow, and is rarely pure white in colour. It is normally about 10 - 18cm in height, with a cap that is about 5 - 15cm in diameter. The gills on the underside of the cap are white, are not directly attached to the stem, and are fairly crowded together. The cap is covered in radiating fibrous tissue, and has a wave-like edge when mature. The spores of this mushroom are white. Oddly enough, the flesh of this mushroom has a faint odour of rose petals; this is an extremely important sign. It is found mostly in the autumn, but also in the summer.

Destroying Angel (Amanita virosa)

This pure white mushroom is actually quite beautiful, but its beauty is only skin deep; like the Death's Cap, this is a lethal mushroom. It's best to stay away from any totally white mushrooms that you come across, even if you think they're safe, because the Angel resembles several other harmless or edible species.

Identifying Characteristics

This mushroom has a hemispherical cap, almost like an inverted bowl or saucer, although this has a tendency to flatten out with time. Also, it has a slightly unpleasant taste and smell, in addition to being totally and completely white. When dry, the cap will feel silky; when wet, the cap will become slimy to the touch. This species often loses its ring, so don't use the presence or absence of a ring to identify it. It is normally about 10 - 18cm tall, with a cap that is about 5 - 10 cm in diameter, and is usually found in summer and autumn.

Additional Mushroom Facts

• Mushrooms are fungi, and so are neither plants nor animals. They belong to a totally different branch of living things.

• Mushrooms are also known as 'toadstools', although many people use this word to describe inedible mushrooms.

• The mushroom is actually only a small part of the entire fungus. The part above ground that we see is a fruiting body, known as a sporophore or hymenium, designed to spread reproductive material in the form of spores. Most of the fungus is made up of a complicated underground network of filaments, called the mycelium. The individual filaments are known as hypha (plural, hyphae). Mushrooms form when two different mycelia meet and fuse, producing fruiting bodies.

• Fungi contain no chlorophyll, and so are unable to photosynthesize. They digest decaying organic material or parasitize other living things, including animals and insects. Athlete's Foot is an example of a fungus that parasitizes humans.

• Many cultivated mushrooms are grown deep underground in caves, cellars, and other damp, dark places. A variety of different growth mediums are used, although the most common one is manured soil.