E-Flora BC: Electronic Atlas of the Flora of British Columbia

Polygonum achoreum S.F. Blake
Blake's knotweed (leathery knotweed)
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants

© Virginia Skilton  Email the photographer   (Photo ID #89150)

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Distribution of Polygonum achoreum
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Species Information

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Annual herb from a taproot; stems prostrate to ascending, several, branched, ridged, bluish-green, 10-70 cm tall/long.
Basal leaves lacking; stem leaves alternate, oval to egg-shaped, rounded at the tips, crowded and overlapping, blue-green to bright green, the blades 1-3 cm long, reduced upwards, the stalks short, jointed; stipules jagged, 5-11 mm long.
Inflorescence of 1-3 flowers in axils of leaves or bracts; perianths 2.5-3.5 mm long, pear-shaped, 5-lobed less than 1/2 the distance to the base, greenish with narrow white or sometimes pinkish borders.
Achenes, more or less 3-sided, yellowish-green to tan, dull, slightly but uniformly pimply, 3 mm long.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry roadsides and disturbed sites in the lowland and steppe zones; infrequent in BC east of the Coast-Cascades Mountains N to 53degreeN; N to AK, E to NF and S to NY and CO.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Polygonum achoreum

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 964 1372 1780
Slope Gradient (%) 2 4 7
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
282 281 282
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 5 6
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: BWBS(1)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Polygonum erectum L.
Polygonum erectum subsp. achoreum (S.F. Blake) A. L÷ve & D. L÷ve

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References