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

Polygonum polygaloides Wall. ex Meisn.
milkwort knotweed (close-flowered knotweed (ssp. confertiflorum); Kellogg's knotweed (ssp. kelloggii))
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants

© Ryan Batten  Email the photographer   (Photo ID #25861)

E-Flora BC Static Map
Distribution of Polygonum polygaloides
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Species Information

Annual herb from a taproot; stems erect or ascending, solitary, usually freely branched, smooth, angled, 1-15 cm tall.
Basal leaves lacking; stem leaves alternate, linear, the blades 10-40 mm long, unstalked; stipules ragged, 4-8 mm long.
Inflorescence a terminal, spikelike raceme, closely crowded and usually overlapping, in groups of 1-4 in the axils of white- or green-margined floral bracts; perianths 2-3 mm long, white to red, unequally 5-lobed 2/3 the distance to the base.
Achenes 3-angled, brown to nearly black, dull or shiny, smooth or longitudinally lined, 1.5-2 mm long, sometimes difficult to separate.
Two subspecies occur in our region.

1. Floral bract margins white; achenes brown to nearly black; usually dull, longitudinally grooved......................... ssp. confertiflorum (Piper) Hickman

1. Floral bract margins green; achenes brown, usually shiny, smooth......................... ssp. kelloggii (Greene) Hickman

Source: The Illustrated Flora of British Columbia

Habitat / Range

Wet vernal pools and ditches to dry roadsides and meadows in the montane and subalpine zones; ssp. confertiflorum - rare in SC BC, ssp. kelloggii Greene - rare in S BC; E to SW AB and S to CO, AZ and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Polygonum polygaloides

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) 861 1473 2109
Slope Gradient (%) 0 19 50
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
183 230 309
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 2 5
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: AT(1), CMA(2), ESSF(2), MS(1), SBS(2), SWB(2)


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.

Taxonomic and Nomenclatural Links

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General References