Edible and poisonous mushrooms

Foraging for fungi in nature is a popular pastime for many people. For these enthusiasts the taste and texture of wild mushrooms is incomparable and more than enough reward for the time and effort it takes to seek out these wonderful delicacies.

For the novice, there are no obvious signs indicating which fungi are edible or inedible and which are poisonous. By far the majority of fungi are harmless and the challenge lies in being able to discern edible fungi from those that are poisonous. There is no simple rule of thumb to determine edibility or toxicity, and the only reliable way to establish if a mushroom is edible is to make a positive identification.

Although the number of really dangerous mushrooms is confined to only a few genera, these include some of the most poisonous organisms on earth. The genus Amanita contains many deadly species, with the notorious Amanita phalloides (death cap) responsible for most cases of fatal mushroom poisoning. Some Amanita mushrooms can easily be mistaken for the generally edible Agaricus species. The first signs of poisoning from consuming the ‘death cap’ set in between five and 30 hours after consumption. Initial symptoms may include vomiting, diarrhoea and abdominal pains, but once the toxins reach the blood stream, treatment may be too late – and it is likely that the victim will die from kidney or liver failure, or heart damage.

Not all toxic species are deadly poisonous. Some mushrooms contain a variety of harmful compounds that can cause nausea, diarrhoea, abdominal cramps, constricted blood vessels, hallucinations or alcohol-like intoxication. Genera in this group include Boletus, Lactarius, Marasmius and Russula. In some cases, the toxins are destroyed in cooking.

Other mushrooms affect the central nervous system. These include Amanita muscaria (fly agaric) and species of the Panaeolus and Inocybe genera, which produce toxins that cause blurred vision, profuse sweating, vomiting, hallucinations, delirium and convulsions. These mushrooms are sometimes used intentionally for their hallucinogenic properties. Another genus of hallucinogenic fungi, Psilocybe, has been used for sacred rituals in places such as Central America and Russia. There is strong evidence to suggest that psilocybin, the active compound in these mushrooms, may have wider application in the medical field, specifically in the treatment of depression and anxiety.

Microfungi that grow on stored grains and foodstuffs can cause serious illnesses in humans and animals. Although these organisms are not regarded as edible, they are often not visible to the naked eye and may be ingested inadvertently.

It is vital that you heed the warnings about toxicity mentioned in this guide. If there is any doubt about the edibility of a harvested mushroom, it is best to obtain expert advice and to refrain from eating the specimen.

Foraging for mushrooms

The secret to a successful mushroom hunt lies in knowing one’s ‘hunting ground’. A thorough knowledge of nearby forests or other areas where mushrooms are likely to grow will help you to locate good specimens before they decay or disappear – or get plucked by fellow mushroom gatherers. There is a good chance that the same species will appear in the same spot each year, so make a point of remembering the locations of previously successful harvests.

It is advisable to begin the hunt early in the morning, before sunlight and warmth dry out freshly erupted specimens – and before other foragers find them. However, there’s some benefit in harvesting the more viscid species of mushroom later in the day, when their surface will, to some extent, have dried.

Before setting off, equip yourself with a sharp pocketknife, a small brush to dust off the soil, a large basket or well-ventilated container and tin foil or wax paper to wrap individual specimens. When you fill your basket, take care to place the firmer mushrooms at the bottom and the fragile ones on top.

Mushrooms should be removed carefully, making sure that the entire fruit body is dug out. Avoid simply cutting them off at the base, as the parts left behind will rot and infect the mycelium and no mushrooms will emerge in the area for several weeks.

Try to pick mushrooms in quantities that can be used immediately. Wild mushrooms are best picked, cooked and eaten on the same day. Alternatively, they can be stored in a cardboard box in the fridge for a day or two, depending on the species (the cardboard container may prolong their shelf life). Avoid washing mushrooms with water as they can get soggy. Rather wipe them with a damp cloth.

Mushrooms can be frozen, as long as they are cooked beforehand, but should be eaten within two months of freezing. Some edible mushrooms can be dried for later use; their flavour becomes more intense as they dehydrate.

Tips for foragers

Mushroom poisoning is very unpleasant and could result in death, so learning how to distinguish between poisonous and edible mushrooms is essential for any mushroom collector.

The following guidelines should be observed when collecting mushrooms.

• When starting out as a mushroom collector, it is advisable to apprentice yourself to an experienced and knowledgeable forager or mycology expert.
• Some poisonous mushrooms look very similar to edible ones, so make sure you are familiar with the dangerous species.
• Pick only whole, fresh specimens as some mature mushrooms may cause food poisoning. Avoid mushrooms that smell rotten, look wilted or mouldy, or are infested with insects. If you are in doubt about a mushroom’s edibility, do not use it in cooking until it can be identified.
• Store each species separately once picked. Paper bags are preferable to plastic, as the latter will result in rapid deterioration of the mushrooms.
• When in doubt about a mushroom’s edibility, wrap it separately from the edible species and store it in a different container for positive identification later.
• Avoid eating raw mushrooms; some may cause unpleasant side effects when consumed. In some species, the harmful compounds can be destroyed during cooking.
• Clean insects and dirt from the mushrooms before cooking them.

As a precaution, the edibility or toxicity of mushrooms featured in this book has been clearly indicated on the species pages.

A brief introduction outlines the basic anatomy and biology of mushrooms and the vital role they play in sustaining all life. There are also guidelines to foraging and to photographing mushrooms and a small selection of simple but delicious mushroom recipes.

Packed with more than 850 photographs, this is both a practical guide and a beautiful book that will inspire nature lovers, foragers, epicureans and anyone curious about these extraordinary life forms.
https://www.penguinrandomhouse.co.za/book/field-guide-mushrooms-other-fungi-south-africa/9781775846543