Belonging to one of the oldest lineages of ferns, the Adder’s-tongue is often termed a ‘living fossil.’ Its name derives from the distinctive spore-bearing spike that protrudes from its singular, tongue-shaped leaf, resembling a snake's tongue. This unique structure sets it apart from more familiar fern species.

Much of the Adder’s-tongue's life is spent beneath the soil as a rhizome. Its underground phase relies on a symbiotic relationship with mycorrhizal fungi, which provide essential nutrients. This subterranean lifestyle allows the fern to persist for years without producing above-ground leaves, emerging only when conditions are favourable.

Remarkably, the Adder’s-tongue fern holds the record for the highest number of chromosomes among known plants. While humans have 46 chromosomes, some species within the Ophioglossum genus possess up to 1,260 chromosomes, highlighting its unique genetic makeup.

Adder’s-tongue has also held a special place in human history and culture. In the past, it was believed to have magical properties, with some people carrying a piece of the plant to protect against snake bites. It was also used in traditional medicine to treat wounds and inflammation.

There are two other closely related plants, the small adder's-tongue fern and the least adder's-tongue fern, both of which are much smaller and rarer, and are only found at a few sites around the south-west of England.

In Hampshire, Adder’s-tongue thrives in ancient, unimproved grasslands and meadows - areas untouched by modern agriculture. Management practices, including careful grazing and habitat restoration, support the delicate ecosystems that these ancient ferns depend upon. Hampshire and Isle of Wight Wildlife Trust plays a pivotal role in preserving these habitats, ensuring that species like the Adder’s-tongue continue to flourish. 

Adder’s-tongue ferns typically appear in late spring and early summer, so now is the perfect time to keep an eye out for them. The fern is an unusual as along with growing on grasslands and meadows, it also grows on hillsides, along woodland rides and on sand dunes. It can typically be found alongside common spotted-orchids, quaking Grass and devil's-bit scabious.

It is considered a good indicator species of ancient meadows. Their presence is a sign of ancient, undisturbed grasslands - an encouraging reminder of the richness and resilience of Hampshire’s natural heritage.