Marsh mermaidweed

Description

Proserpinaca palustris, the marsh mermaidweed or common mermaid-weed, is a species of flowering plant in the watermilfoil family (Haloragaceae). It is found in North America, the Caribbean, and Central America. It has submerged leaves, which are sessile, 2–6 cm (1–2 in) long. They are deeply divided into linear segments and the emergent leaves are simply serrated. It has fruits with concave sides and sharp or winged angles. It grows in swamps, bogs, ponds and marshes. There are two known varieties; P. palustris var. palustris - which has fruits 4-6mm wide, angles wing margined, very rare SE and NW P. palustris var. crebra (Fernald and Griscom) - which has fruits 2-4mm wide, angles not winged, occasional E and NW 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). Two or three extant species are known from this genus, depending on the treatment. They are: Proserpinaca intermedia - Uncommon in the southeastern U.S.; intermediate in characteristics, and it is unclear if it is best treated as a hybrid Proserpinaca palustris - Widespread in eastern North America and the West Indies Proserpinaca pectinata - Native primarily to the Southeast Coastal Plain, with disjunct populations in middle Tennessee