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.

Sometimes called 'Wild spinach', Sea beet can be cooked and eaten. It grows wild on shingle beaches, cliffs and bare ground near to the sea, as well as in saltmarshes.

Bladder campion is so-called for the bladder-like bulge that sites just behind the five-petalled flower - this is actually the fused sepals. Look for it on grasslands, farmland and along hedgerows…

The sessile oak is so-called because its acorns are not held on stalks like those of the familiar English oak. It can be found in woodlands mainly in the north and west of the UK.

Small-spotted catsharks used to be called lesser-spotted dogfish - which might be what you know them best as. It's the same shark, just a different name!

The tightly packed, thistle-like purple flower heads of common knapweed bloom on all kinds of grasslands. Also regularly called black knapweed, this plant attracts clouds of butterflies.

The smaller of our two UK seal species, common seals are also known as harbour seals. Despite being called "Common", they are actually less common than grey seals!

Heather is also called 'ling'. Look for it on our heaths, moors and bogs, where its delicate, loosely arranged pink flowers attract all kinds of nectar-loving insects.

As its name suggests, the house martin can be spotted nesting in the eaves of houses in our towns and villages. Its intricate mud nests take days to build and are often returned to and used in…