The Common walnut tree produces a large, brown nut that is familiar to so many of us. It is an introduced species in the UK, and can be seen in towns, gardens and parks.

The common octopus is a highly intelligent, active predator. It even has a secret weapon - special glands produce a venom that it uses to incapacitate its prey!

A scrambling plant, Common vetch has pink flowers. It is a member of the pea family and can be seen on grassland, farmland and waste ground, as well as at the coast.

An easily overlooked orchid, the Common twayblade is yellow-green and less showy than other UK orchids. Look for it in woodlands and grasslands on chalky soils, in particular.

Look for the small, white, star-shaped flowers of Common chickweed all year-round. Sometimes considered a 'weed', it is still a valuable food source for insects.

Sometimes called 'Marsh samphire', wild common glasswort is often gathered and eaten. It grows on saltmarshes and beaches, sometimes forming big, green, fleshy carpets.

Common mallow is a handsome 'weed' of waste ground, roadside verges and gardens. Its deep pink, stripey flowers provide nectar for insects throughout the summer.

The Common clubtail is on the wing in spring and summer. It is an elusive dragonfly that is easiest to see when it first emerges. It can be found along rivers in Southern England and Wales.

A low-growing plant of sand dunes, heaths and grassy places, Common centaury is in bloom over summer. Look for clusters of pretty, pink, five-petalled flowers.