Proserpinaca, commonly called mermaidweed, is a genus of flowering plants in the watermilfoil family (Haloragaceae). It is a small genus, comprising only two to three extant species, all of which are native to eastern North America and the West Indies. All species in this genus are found in aquatic or terrestrial wetland habitats.

Proserpinaca can be distinguished from its relative Myriophyllum by having 3 stamens and carpels per flower (as opposed to having 4 or 8).

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