perigone

pusilla mainly by its bigger perigone with broader and less depth concavity, outer tepals with narrowed claws, inner tepals with blades markedly narrower, and longer upwards, and with glandular trichomes spreading in a small area, stamens shorter, with porrect filaments, smaller anthers, and broader connective.

Cypella uliginosa is easily segregated from other species of the section Nais, mainly by the perigone with scarcely deep central concavity, and inner tepals with deeply folded blade.