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

Polygonum majus (Meisn.) Piper
wiry knotweed
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #89186)

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Distribution of Polygonum majus
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Species Information

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General:
Annual herb from a small taproot; stems ascending to erect, numerous, simple to freely branched, 10-40 cm tall.
Leaves:
Basal leaves lacking; stem leaves alternate, linear to narrowly oblong, egg-shaped or elliptic, the blades 1-8 cm long, unstalked or nearly so, sometimes reduced to bracts above; stipules short-sheathing, 5-12 mm long, clear, becoming ragged.
Flowers:
Inflorescence of few flowers in elongate axillary racemes; perianths 1.5-5 mm long, greenish with white or pinkish margins, 5-lobed nearly to the base.
Fruits:
Achenes, lanceolate to egg-shaped, sometimes 3-angled, black, smooth and shiny, 2-4 mm long.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry grasslands, shrublands, rocky slopes and forest openings in the steppe and montane zones; infrequent in SC BC; S to ID, W MT and CA.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Polygonum majus

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

Minimum

Average

Maximum
Elevation (metres) 350 691 1180
Slope Gradient (%) 4 30 70
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W] 		20 198 334
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric] 		1 2 5
Modal Nutrient Regime
Class		 C
Number of field plots
 species was recorded in:		 29
Modal BEC Zone Class
 PP
All BEC Zones (# of stations/zone) species was recorded in: BG(7), ICH(1), IDF(5), PP(13)

Climate

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 coarctatum var. majus Meisn.
Polygonum douglasii subsp. majus (Meisn.) J.C. Hickman

Taxonomic and Nomenclatural Links

Flora North America treatment for Polygonaceae
 Flora North America treatment for Polygonum majus
Genetic information (NCBI Taxonomy Database)
 International Plant Names Index
 Taxonomic Information from the World Flora Online
 Integrated Taxonomic Information System

Additional Photo Sources

Images From CalPhoto
UT Austin's Native Plant Database
 Google Image Search
 Flickr Image Search

General References

Google Scholar Search
Family References
 General Botanical References for BC
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-05-09 8:21:51 PM ]
Disclaimer: The information contained in the E-Flora atlas pages is derived from expert sources as cited in each section. This information is scientifically based. E-Flora also acts as a portal to other sites via deep links. As always, users should refer to the original sources for complete information. E-Flora BC is not responsible for the accuracy or completeness of the original information.
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