An investigation is under way after three strands of a rare fungus were taken from the New Forest.
The Forestry Commission said three specimens of the protected Hericium erinaceus had been cut and removed earlier this month.
It is thought it could have been taken to be used in cooking, as restaurateurs have been suspected of large-scale foraging in the forest.
Hampshire Constabulary has confirmed it is investigating.
The fungus, which is classified as rare in the UK, is usually found on dead wood on broad-leaved trees.
A Forestry Commission spokeswoman said: "Taking of rare species ..from anywhere by anyone is illegal and incurs high penalties.
"New Forest is also one of the most important designated sites in England for fungi, with a lot of endangered species, which can easily be mistaken for varieties that are picked for eating."
Also known as Lion's Mane or Old Man's beard, Hericium erinaceus has been used for centuries in Chinese medicine and has been studied for anti-cancer and diabetes properties.