Hydrocallis are perennial, rhizomatous, aquatic herbs with contractile roots.

The floating, petiolate leaves are orbicular to elliptic and have an entire margin.

[6][4] The carpels have enlarged, clavate carpellary appendages.

[6][1] The flowers emit solvent-like, pungent, fermented, or fruity fragrances.

Later, it was elevated to the status of the subgenus Nymphaea subg.