Social media influencers and other visitors to Epping Forest are being urged to leave the wild mushrooms untouched.
The City of London Corporation, which manages the park in north London, has warned against picking the fungi - an act which is strictly banned and illegal under forest bylaws.
It comes amid reports of content creators and social media users posting videos of foraging mushrooms, inadvertently encouraging others to do the same.
Many of the creators are unaware of the restrictions in place at the over 8,000-acre forest.
There have been early appearances of certain fungi like the “Chicken of the Woods,” following warm weather, which has drawn more visitors to the site for mushroom hunting.
Visitors are permitted to photograph the fungi, but should leave it and other wildlife exactly as they found it.
Epping Forest is nationally recognised for its fungal diversity and is home to more than 1,500 species of fungi, including some endangered species.
Chair of the City Corporation's Epping Forest and Commons Committee, Caroline Haines, said: "Epping Forest is one of the country's most important habitats for fungi, and many species depend on being left undisturbed.
"We know people are fascinated by mushrooms and want to share their discoveries online. Many influencers and visitors may not realise that picking fungi is not permitted in the Forest, but posts showing mushrooms being collected can encourage others to follow suit.
"We want everyone to enjoy the Forest and experience its remarkable wildlife. Our message is simple: click, don't pick."
The City of London Corporation has several open spaces all across London, including Burnham Beeches, where a species new to science was discovered.
Epping Forest was home to the UK’s first confirmed record of the rare fungus species, Russula bluminana, last year.
