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Lythraceae: Decodon verticillatus (L.) Ell.
(swamp-loosestrife, water willow)

This member of the Nova Scotia's Coastal Plain Flora is a shrubby aquatic perennial occurring "at the edge and trailing or arching into the water, the stems with a light corky thickening where submersed, 6-25 dm. long".1 flowers Stems root at tips when they touch the soil. The species has opposite or 3- or 4-whorled, willow-like leaves with entire (smooth) margins. Lavender flowers occur in clusters in upper leaf axils; they are 4- or 5-petaled, perfect, regular flowers with parts arising from a hypanthium. In Nova Scotia the species flowers in July and August. Roland et al., comment that "Ours is var laevigatus T&G, the northern type with the pedicels and undersides of leaves smooth."2 versus the finely downy leaevs and stems of typical plants1. Var laevigatus is currently considered a synonym, not an accepted variety.3

Decodon verticillatus occurs in the southwest part of the province and at one location in Cape Breton. It is broadly distributed over Eastern North America, plus Texas, but is not found in Newfoundland. It has an S rank of 2-3 (rare to uncommon) for Nova Scotia and is considered At Risk (S1) in P.E.I. and New Brunswick. It is yellow listed under the Nova Scotia DNR General Status Rankings.

Sources | Notes & Refs | Selected Web Resources | Line Drawing

Click on images for larger versions.

August 1, 2008. Shelburne County: Roseway River, by water's edge.
Photographer: JackPine. Notes

Decodon verticillatus, habitat


Decodon verticillatus, habit

Habit: growing on top of and amongst leatherleaf.

Decodon verticillatus, arching plant

Arching plant, tip rooted in soil. See Notes for comments on orientation of leaves and flowers.



Selected Web Resources

Notes & References

  1. Fassett, N.C. and Ogden, E.C. 1957. A manual of aquatic plants. Madison: University of Wisconsin Press.
  2. Roland, A.E., Zinck, M. and Owen, E. 1998. Roland's flora of Nova Scotia, 3rd Ed. Halifax: Nimbus & Nova Scotia Museum.
  3. ITIS Canada [Accessed 29 Aug. 2008]