[1] Nymphaea rapinii is an aquatic herb[2] with stoloniferous, cylindrical tubers.

The reddish-purple, glabrous, non-brittle, petioles have two primary and eight secondary peripheral air canals.

[3] The elliptic, suborbicular to orbicular leaf blade has an entire and flat margin and actinodromous, arachnoid venation with impressed veins.

[2] The gabrous, brownish, non-brittle peduncle has five primary central and ten secondary peripheral air canals.

[3] The specific epithet rapinii honours Prof. Dr. Alessandro Rapini of the State University of Feira de Santana, Brazil.