Oxalis natans

Oxalis natans, commonly water sorrel or in Afrikaans waterklawer (water clover) or watersuring (water sorrel) in Afrikaans is an aquatic perennial. The white, cup-shaped flowers and leaves are on the water.

Today it is probably only growing in a few places, notably the Elandsberg Private Nature Reserve where this photo was taken, a farm near Stellenbosch and a dam near Agulhas (Manning, 2007; Bond and Goldblatt, 1984; iNaturalist).