The river lamprey is a primitive, jawless fish, with a round, sucker-mouth which it uses to attach to other fish to feed from them. Adults live in the sea and return to freshwater to spawn.

Look for Water avens in damp habitats, such as riversides, wet woodlands and wet meadows. It has nodding, purple-and-orange flowers that hang on delicate, purple stems.

It's easy to see where the compass jellyfish got its name – its brown markings look just like a compass! They may look beautiful – but they give a nasty sting so keep your distance.

A small and delicate plant of chalk grasslands, Fairy flax can be seen in bloom from May to September - look out for its nodding, white flowers.

Look out for this large, leafy lichen on trees in ancient woodlands in the west of the UK.

A late-blooming flower, Meadow saffron looks like a crocus, displaying similar pink flowers once its leaves have died back. It is a highly poisonous plant of meadows and woodland rides and…

The true fox-sedge is a rare and threatened plant in the UK. It relies on lowland floodplain meadows and damp habitats, which are rapidly disappearing. Look for reddish-brown flowers in summer.…

A short, but pretty plant of unimproved grasslands, the Green-winged orchid gets its name from the green veins in the 'hood' of its flowers. Look for it in May and June.

Look for the unusual flowers of lords-and-ladies in spring woodlands: a pale green sheath surrounds a spike of tiny, yellow flowers. This spike eventually forms a familiar, short stalk of striking…