Never eat a wild mushroom identified only from a website, a book or an app. Have every find checked in person by an expert, such as a mycological society.
Identification
Hericium erinaceus produces a single, compact, rounded fruit body without branches, 10–30 cm across, attached directly to the wood. From its surface hang numerous long, soft, crowded spines, usually 1–5 cm long, white when fresh and turning cream to yellowish or brownish with age. The flesh is white, soft and stringy, with a texture often compared to crab or lobster when cooked.
The spore print is white; the spores are small, smooth to finely roughened and amyloid. Related species form branched fruit bodies: Hericium coralloides and Hericium americanum have many branches bearing shorter spines, while the unbranched, long-spined form is typical of lion's mane.
Habitat and ecology
Lion's mane is a white-rot fungus that colonises the heartwood of old broadleaf trees, especially beech and oak, often entering through wounds, and continues to fruit on dead trunks and logs. It occurs in temperate Europe, Asia and North America. In Europe it is rare and associated with old, deadwood-rich broadleaf forests; it is considered threatened in many countries because such habitats have declined. Fruiting is mainly from late summer to autumn.
Uses and importance
Lion's mane is a good culinary mushroom, sliced and fried in butter, used as a seafood substitute, or added to soups; it absorbs flavours well and should be cooked thoroughly.
Research has studied two groups of compounds: hericenones from the fruit body and erinacines from the mycelium, which stimulated nerve growth factor synthesis in cell experiments and showed effects on nerve and brain parameters in animal studies. A small number of small human studies, for example a Japanese trial in older adults with mild cognitive impairment, have reported limited effects. These findings do not prove that lion's mane prevents or treats any disease. In the EU, mushroom supplements are regulated as food, and health claims may only be used if authorised under Regulation (EC) No 1924/2006. Consult a doctor before taking supplements.
Cultivation
Lion's mane is easy to grow indoors on supplemented hardwood sawdust in bags or bottles, sterilised before inoculation. Spawn run is at about 21–25 °C, and fruiting is induced at roughly 15–22 °C with very high humidity and fresh air; dry air causes yellowing and stunted spines, while high CO₂ produces branched or coral-like fruit bodies. It can also be grown outdoors on hardwood logs. Harvest when the spines are elongated but before the fruit body yellows. Cultivation is the best way to enjoy this species without harming rare wild populations.
Safety and edibility
Lion's mane is edible when correctly identified and cooked; rare allergic reactions, including skin and respiratory symptoms, have been reported. People with mushroom allergies should be cautious.
Because wild populations are rare, please leave wild fruit bodies to sporulate. Never eat a wild mushroom based on a website or photo: identification must be confirmed in person by an expert such as a mycological society or a trained mushroom adviser. There are no deadly look-alikes among the tooth fungi on wood, but related Hericium species are also rare and should be protected.
If you suspect mushroom poisoning, call 999 in an emergency or NHS 111 for urgent advice straight away, even before symptoms appear, and keep the remains of the mushrooms.
Look-alikes
Hericium coralloides, the coral tooth, is richly branched with short spines along the branches. Hericium cirrhatum forms overlapping brackets with spines below and a rough upper surface. Hericium alpestre (syn. H. flagellum) grows on fir. Hedgehog mushrooms of the genus Hydnum grow on the ground and have caps with spines underneath.
In the UK
In Britain this fungus, known here as the bearded tooth, is rare and legally protected: it is listed on Schedule 8 of the Wildlife and Countryside Act 1981, so it is an offence to pick, uproot or destroy wild specimens or to sell them. It grows on old beech and oak, often high on veteran trees.
All lion's mane sold fresh, dried or in supplements in the UK should come from cultivation. No health claims for mushrooms themselves are authorised on the GB nutrition and health claims register, according to the Advertising Standards Authority.
