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.

Look for the White water-lily in still and slow-moving water, such as ponds, ditches, lakes and canals. Its lily pads and massive, white flowers float at the water's surface.

Look for the Yellow water-lily in still and slow-moving water, such as ponds, ditches, lakes and canals. Its lily pads and cupped, yellow flowers float at the water's surface.

Found in ponds and marshes, the fragile look of the Common water-measurer belies its fierce nature. A predator of small insects, it uses the vibrations of the water's surface to locate its…

Look out for the feathery leaves of Spiked water-milfoil just below the surface of streams, ditches, lakes and ponds; its red flowers emerge from the water in summer. It provides shelter for a…