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Wisconsin Plant of the Week

Comarum palustre L.

Rosaceae (Rose Family)

Common Name:

marsh cinquefoil

06/24/2001

Marsh cinquefoil is a native perennial in bogs, conifer swamps and acidic to neutral marshes. It anchors near the shoreline in muck or peat soil, and then the flexible reddish stem spreads out with leaves and flowers emerging over the surface of the water. Commercial cranberry growers consider it a weed, but otherwise itís associated with higher quality natural areas.  

Wisconsin has over 180 taxa in the Rose family, and marsh cinquefoil is one of the few that grow in the water. It has all the typical Rose family characters -- 5-parted flowers, where the petals are separate and the sepals are joined just at the base; many stamens that remain on the flower after the petals fall off; and leaves with stipules where they attach to the stem.  Like all the herbaceous members of the Rose family, marsh cinquefoil has compound leaves.

The flowers are 2 cm across and bloom from late June through July when not much else is in bloom. They have 5 narrow deep maroon petals, about half as long as the 5 broad, pointed red sepals.  Leaves are pinnately compound on long stalks with 5 to 7 leaflets.  Leaflets are ellipse shape, up to 10 cm long, and have toothed edges.

Marsh cinquefoil spreads by rooting at the nodes along the stem and propagates by rhizome and seed.

Geum rivale, Purple avens, is another Rose family member of wet habitats with deep red flowers.  Geum have rounded petals, smaller flowers and the terminal leaflet is much enlarged.

  • Origin of the name: Formerly Potentilla palustris.  Use of Comarum is unclear -- Comarum is the Greek name for the strawberry tree, Arbutus unedo, which is in the very different Ericaceae family; palustre, L., palus, marsh
  • Range: Circumboreal, s. to NJ, IA, CA
  • WI Range:  Statewide
  • Common associates: Leatherleaf, bog bean, arrowhead
  • Wetland Indicator Status: OBL
  • Coefficient of Conservatism: C = 10 (S&W), C = 7 (MI)
     
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