Proserpinaca palustris

Mermaid-Weed

MARSH CINQUEFOIL

NATIVE TO MAINE

Habitat: Mermaid weed grows in the submersed and emergent plant community. It may be found in the shallow waters of bogs, marshes, swamps, and along the muddy shores and banks of ponds and streams. This plant may “morph” to a terrestrial form when water levels drop.

Description: The reddish-brown stems of mermaid weed emerge from a long trailing rhizome. The leaves (5 to 10 cm long) are arranged alternately on the stem and typically more than one leaf-type occurs on a single plant. The lower (earlier, submersed) leaves generally tend to be feather-like divided. The upper (later, emergent) leaves, typically associated with flowering and fruiting, tend to be more blade-shaped and are conspicuously serrated. The reddish-purple flowers (2 cm wide) occur in the leaf axils of the emergent leaves, followed by three-sided fruits (or “nutlets”).

Origin and Range: Mermaid weed is native to much of the US including New England.

Annual Cycle: Mermaid weed overwinters by dying back to its rhizomes and rootstalks. New growth emerges in the spring, leaves developing by early summer. Flowering occurs by mid-summer. Reproduction occurs by seed, and vegetatively by rhizomes and rootstalks.

Value in Aquatic Community: Shorebirds and waterfowl feed upon the seeds of mermaid weed, and aquatic invertebrates and fish use the trailing leaves and stems for food and shelter.

Look Alikes: The submersed leaves of mermaid weed may be confused some water-milfoil species.