A tall and robust species of sedge, the Great fen-sedge has long leaves with sawtooth edges. It forms dense stands in lowland fens and around lakes.

Largely confined to the north of the UK, the rare pine marten is mostly nocturnal and very hard to spot. Reintroductions are helping it make a comeback.

One of the most colourful fish in UK seas, the cuckoo wrasse looks like it belongs in the tropics. Don't be fooled though, it's very much a native species.

The white-clawed crayfish is a freshwater, bronze-coloured crustacean with pale undersides to its claws - hence the name. It is under threat from an invasive and introduced species of crayfish.…

Buddleia is a familiar shrub, well-known for its attractiveness to butterflies. It is actually an introduced species, however, that has become naturalised on waste ground, railway cuttings and in…

Their empty, delicate pink or yellow shells can often be found washed up on beaches, but the animals themselves live buried in the sand all around the coasts of the UK.

Traditionally a coastal species, Lesser sea-spurrey has spread inland, taking advantage of the winter-salting of our roads. Its pink-and-white flowers bloom in summer.