The thick topshell is a common sight on rocky shores in Wales and South West England.

Fennel has feathery leaves and open, umbels of yellow flowers. It was probably introduced by the Romans for culinary use, and is now a naturalised species of verges, waste ground and sand dunes.…

As its name suggests, Himalayan balsam is from the Himalayas and was introduced here in 1839. It now an invasive weed of riverbanks and ditches, where it prevents native species from growing.

An introduced species, the rhododendron leafhopper is a striking mix of green and red, with a black stripe across its face. It can be found feeding on rhododendrons (also introduced) in Southern…

Cotoneaster was introduced to the UK in 1879 from Eastern Asia as an ornamental plant. It is now an invasive non-native species which is taking over valuable habitats including limestone…

Lilac is an introduced species in the UK that can sometimes be found in hedgerows and along woodland edges. Flower spikes appear in spring, beautifully scented and packed with small, lilac-pink…

This purply-brown seaweed is a common feature on our rocky shores and on our dinner plates.

This beautiful beetle only arrived in the UK in 1960s but is now a common sight on garden herbs.

The four-spotted chaser is easily recognised by the two dark spots on the leading edge of each wing - giving this species its name. It can be seen on heathlands and near ponds and lakes.

The London plane tree is, as its name suggests, a familiar sight along the roadsides and in the parks of London. An introduced and widely planted species, it is tough enough to put up with city…