This member of the Gunneraceae family was given this name by Carl Linnaeus in 1767. It is found in Burundi, Congo, Eswatini, Ethiopia, Kenya, Lesotho, Mozambique, Rwanda, South Africa, Sudan; Tanzania, Uganda, Zaïre, Zimbabwe and even on Madagascar. It can be found along rivers and creeks, growing in a rich soil with lots of water and some to lots of sun. The rhizomes can grow to three centimetres in diameter and a meter long. Depending on the conditions, the plant grow from fifteen centimetres to one meter. The flowers are from pink over pale violet to reddish brown. Also seen as a member of the Haloragaceae family. Named after Johan Ernst Gunnerus,1718-1773, Bishop of Trondheim - and botanist. The species name from Latin, perpenso: 'weigh exactly'.