This enormous water beetle is as rare as it is impressive.

Large scale drainage in the UK has seen a massive reduction in the range of this sensitive aquatic plant which now only occurs in around 50 sites in England.

Look out for the white, umbrella-like flower heads of lesser water-parsnip along the shallow margins of ditches, ponds, lakes and rivers. When crushed, it does, indeed, smell like parsnip!

Water-plantain is an aquatic plant of shallow water and muddy banks. In bloom over summer, it displays tall branches of loosely clustered, pale lilac flowers.

Water-cress has become so popular as a salad addition that it is now cultivated on a wide scale. In the wild, it grows in shallow, fast-flowing streams and is an indicator of clean water.