Perennials with vertical rhizomes to 30 cm long and 4 c. thick with long anodal stolons produced at the apex of the rhizome.
Leaves floating or, when crowded, almost erect, broad-elliptic with a radial slit, to 25 cm long, upper surface may have brown markings c. 10 mm diam.; margins slightly sinuate.
Flowers to 12 cm diam. Sepals 4, green. Petals numerous, acute, yellow, grading into petaloid stamens. Ovary lobes large with stigmatic surface on lower 60%.
Seeds rarely formed.