Persicaria amphibia is a highly polymorphic aquatic species with two recognized but intergrading varieties in North America: var. emersa and var. stipulacea (Flora North America 2010). Both are widespread in the US and Canada, with a few exceptions in the northwest and southeast (USDA 2010). Plants which bloom in water, or are sometimes stranded on land during draw down periods, are recognized as var. stipulacea, while plants that bloom on moist soil are recognized as var. emersa (Flora North America 2010). Aside from habitat, characters that separate the two varieties include habit (erect or prostrate) and inflorescence shape.
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General:
Perennial herb from a rhizome or stolon; stems prostrate and freely rooting to ascending, several, simple, with erect tips and flowering branches up to 30-80 cm tall/long.
Leaves:
Basal leaves lacking; stem leaves lanceolate to egg-shaped, usually floating, smooth above, hairy to smooth below, the blades 5-15 cm long, the stalks up to 1/2 as long as the blades; stipules smooth to hairy, cylindric, 1-2 cm long.
Flowers:
Inflorescence of 1 or 2 terminal or subterminal, spikelike panicles, 1-8 cm long, 1-2 cm wide; perianths scarlet to rose, 4-5 mm long, 5-lobed.
Fruits:
Achenes, lens-shaped, brown to black, smooth, shiny or sometimes dull, 2.5-3 mm long.
Notes:
Two intergrading varieties occur in BC:
1. Stalks usually glandular-hairy; inflorescence usually at least 4 cm long, cylindric................... var. emersa Michx.
1. Stalks usually smooth; inflorescence rarely 4 cm long, egg-shaped.................... var. stipulacea (Coleman) Fern.
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Site Information |
Value / Class |
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Avg |
Min |
Max |
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Elevation
(metres) |
933 | 55 | 2120 |
Slope
Gradient (%) |
0 | 0 | 20 |
Aspect (degrees) |
119 | 0 | 186 |
Soil
Moisture Regime (SMR) [0 - very xeric; 4 - mesic; 8 - hydric] |
7 | 1 | 8 |
Modal
Nutrient Regime
Class |
D | ||
#
of field plots species was recorded in: |
173 | ||
Modal
BEC Zone Class |
IDF | ||
All BEC Zones (# of stations/zone) species was recorded in |
BAFA(1), BG(6), BWBS(5), CDF(2), CWH(1), ICH(7), IDF(81), MS(5), PP(9), SBPS(25), SBS(30) | ||
Source:
Klinkenberg 2013
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Synonyms and Alternate Names:
Polygonum amphibium L.
Polygonum amphibium var. emersum Michx.