Native Oysters are a staple of our seas and our plates - but our love of their taste has lead to a sharp decline all around the UK.

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 variable damselfly looks a lot like the azure damselfly, but is much less common throughout most of the UK.

Red squirrels are native to the UK but are a lot rarer than their grey cousins. They live in a few special places across the UK thanks to reintroduction projects.

The Common fragrant-orchid lives up to its name: it produces a sweet, orangey smell that is very strong in the evening. Look for its densely packed, pink flower spikes on chalk grasslands in…

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!

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.