In marshy conditions Echinodorus palaefolius var. latifolius from Brazil has round leaves with a horizontal leaf base.
Under water the leaves are narrower and longer (from 20-40 cm, and a 20-40 cm wide roset). In the aquarium it tends to grow out of the water. This can be prevented by removing the long leaves just before they reach the water surface. The next leaves will then become shorter and the plant will remain under water.
In open aquariums the plant can be allowed to grow out of the water, but the leaf margins often dry out if air humidity is low.