Marsh fritillary
This beautiful butterfly is one of our rarest, now mostly restricted to the western parts of the UK.
Marsh frog
Europe's largest frog is not naturally found in the UK, but was introduced to Kent and has spread throughout the southeast.
Marsh gentian
The bright blue, trumpet-shaped flowers of the marsh gentian contrast deeply with the pinks and purples of the wet heaths it inhabits. The New Forest holds a large population of this late-flowering plant.
Marsh hair moss
The marsh hair moss is the largest moss in the UK. Look out for it in damp woodland and on boggy heathlands where it forms large, green and spikey 'cushions'.
Marsh harrier
The courtship of the marsh harrier is certainly a sight to behold - wheeling and tumbling through the sky, male and female partners lock talons in mid-air. Look out for this rare bird over reedbeds in East Anglia, Somerset and the South East.
Marsh helleborine
The Marsh helleborine is a beautiful orchid of fens, wet grassland and dune slacks. Growing in profusion in places, look for reddish stems and white-and-pink flowers.
Marsh tit
Despite its name, the marsh tit actually lives in woodland and parks in England and Wales. It is very similar to the willow tit, but has a glossier black cap and a 'pitchoo' call that sounds like a sneeze!
Marsh violet
As its name suggests, the Marsh violet likes damp spots, such as marshes, bogs and wet woods. It is a low-growing plant with kidney-shaped leaves and pale lilac flowers.
Marsh-marigold
The large, golden flowers of Marsh-marigold look like the cups of kings, hence its other name: 'Kingcup'. It favours damp spots, like ponds, meadows, marshes, ditches and wet woodlands.
Mauve stinger
This species can pack a powerful sting, so be sure not to get too close!
Meadow brown
One of our most common butterflies, the meadow brown can be spotted on grasslands, and in gardens and parks, often in large numbers. There are four subspecies of meadow brown.
Meadow buttercup
Meadow buttercup is a tall and stately buttercup, with buttery-yellow flowers that pepper meadows, pastures, gardens and parks with little drops of sunshine.