Proserpinaca palustris, the marsh mermaidweed or common mermaid-weed,[4][5] is a species of flowering plant in the watermilfoil family (Haloragaceae).

Proserpinaca palustris is heterophyllous, meaning that its leaves develop different morphology based on the environmental conditions.

Exposure to intense high light or elevated temperatures has the most effect on the submerged shoots of long-day plants, causing them to produce transitional leaf forms.

Proserpinaca palustris has an alternate leaf arrangement and radially symmetrical flowers, whose petals are fused into a cup-like shape.

[10] Proserpinaca palustris is commonly found in freshwater swamps, marshes, bogs, ponds, and shorelines in temperate climates in the Americas.

[11] The Flora of the Southeastern US classifies P. palustris as a secure global species [12] and is most abundant in the coastal plain of eastern North America, though not found in brackish water or saltwater.

Proserpinaca palustris is used commercially as decoration for aquariums, as they grow much slower and smaller in controlled environments like fish tanks.

[13] Proserpinanca palustris gets its name from the myth of Proserpina, or Persephone, the ancient Roman and Greek goddess of spring and the underworld.