Montane. Edges of ponds. Summer.
Lake Haviland Trail, June 28, 2004.

Persicaria amphibia is one of about a dozen common ditch/pond or terrestrial members of this genus (or its very closely related genus, Polygonum) found in the Four Corners region. Both genera are found world-wide; Persicaria has about 100 species and Polygonum about 65 world-wide. Some flora authors do not separate the two genera; most do on the basis of the structure and persistence of the ocrea, the sheathing around the stem.

A number of the plants have "Smartweed" as part of their common name. This Water Smartweed typically roots at the edge of ponds and lakes in shallow water where it floats its leaves and flowers at the end of long stems. It can also be found occasionally out of water in wetlands. 

According to the Flora of North America, the land-adapted plants and the water-adapted plants are now widely regarded as two distinct varieties. However, the Flora of the Four Corners Region disagrees with giving varietal status: "Particularly robust, emergent plants with lanceolate leaves are sometimes recognized as the taxonomically dubious var. emersa".

Persicaria amphibia is found in almost all states and throughout Canada.

In 1753 Linnaeus named this plant Polygonum amphibium.  In 1821 Asa Gray renamed the plant Persicaria amphibia and it is this name that William Weber, the Flora of North America, and the Synthesis of the North American Flora accept. A Utah Flora and the online USDA Plant Database accept Polygonum amphibium.

"Persica" is Latin for "Peach"; "aria" means "pertaining to". The name refers to the similarity of the leaves of the two plants.

Montane. Edges of ponds. Summer.
Lake Haviland Trail, July 23, 2005.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Persicaria amphibia