Sagittaria sagittifolia L.
Plant height 60-100 cm. Flower width 2-2.5 cm.
Arrowhead is a native, semi-aquatic plant which has large aerial arrow-shaped leaves. The white flowers have 3 petals with purple centres.
It flowers July to August, and is found in shallow, still or slow-moving bodies of freshwater like lake margins, ponds, ditches, rivers, streams and canals. Widespread in the south of Britain, but local and scarcer elsewhere.