The Sitka spruce was introduced into the UK from North America in the 19th century. It has been widely planted as a forestry tree; look for classic needle-like leaves and pale brown, domed cones…

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.

In summer, the sedge warbler can be spotted singing from a reed or willow perch in wetlands across the UK. Males never sing the same song twice, adding new phrases to impress the females.

As the name suggests, the Common medium stonefly is found in gravelly upland rivers and streams, often on bankside stones and plants. There are 34 species of Stonefly in the UK, which are hard to…

Often seen carpeting the floor of ancient woodlands, Dog's mercury can quickly colonise, its fresh green leaves shading out rarer plants. It is also very poisonous.

Turn over large stones or paving slabs in the garden and you are likely to find a red ant colony. This medium-sized ant can deliver a painful sting, so be careful! In summer, winged adults swarm…

Sea potatoes may have a funny name, but they are perfectly adapted for life in the sand. They are a type of sea urchin that live in a burrow in the sand, feeding on dead animals and plants using…

The brown, oval, spiky seed heads of the teasel are a familiar sight in all kinds of habitats, from grassland to waste ground. They are visited by goldfinches and other birds, so make good garden…