Best time to see: Jul to Aug

Key facts

An aquatic buttercup found in marshy places, and in and beside streams and ponds

Once common but now, like the wetlands it favours, few and far between

Leaves or roots ground with salt blister the skin and were once used to treat the sores caused by bubonic plague

Extras

Medium perennial with long spear-like basal leaves, sometimes creeping and rooting at leaf junctions

Large glossy yellow flowers, 3–5cm across