An uncommon tree of wet woodlands, riverbanks and heathlands, alder buckthorn displays pale green flowers in spring, and red berries that turn purple in autumn.

An uncommon hedgerow and woodland tree of central and eastern England, purging buckthorn displays yellow-green flowers in spring, and poisonous, black berries in autumn.

Sea-buckthorn is a spiny, thicket-forming shrub of sand dunes. It's native to the east coast of England but considered an invasive species elsewhere. It is most obvious in autumn when it is…

Common alder can be found along riversides, and in fens and wet woodlands. Its exposed roots provide shelter for fish, and its rounded leaves are food for aquatic insects.

The alder fly is a blackish invertebrate, with delicately veined wings that it folds over its body like a tent. It can be found near ponds and slow-flowing rivers; the larvae living in the silt at…