Polygonum arenastrum Jord. ex Boreau
oval-leaved knotweed (oval-leaf knotweed)
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants

Photograph

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Map

E-Flora BC Static Map

Distribution of Polygonum arenastrum
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Species Information

General:
Annual or occasionally perennial herb from a taproot; stems prostrate, ascending or sometimes erect, several, usually 3-angled, at least when young, usually branched, the main branches 10-80 cm tall/long.
Leaves:
Basal leaves narrowly lanceolate to oblong-lanceolate, pale or bluish-green, the blades 5-15 mm long, unstalked, jointed at the base; stem leaves alternate, stem and branch leaves usually similar, reduced upwards; sheathing stipules silvery, 4-6 mm long, ragged.
Flowers:
Inflorescence of 1-5 flowers in axillary clusters; perianths 2-3 mm long, green with pink or white margins, 5-lobed more than 1/2 the distance to the base.
Fruits:
Achenes, with one side concave and two sides convex, brown, dull, pimply in lines,1.6-2.2 mm long.
Notes:
Often mistaken for P. aviculare, a species having stem and branch leaves dissimilar.

SourceThe Illustrated Flora of British Columbia

Illustration

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Habitat and Range

Mesic to dry disturbed sites, roadsides and waste places in the lowland, steppe and montane zones; infrequent in S BC, rare northward to 53degreeN; introduced from Eurasia.

SourceThe Illustrated Flora of British Columbia

Synonyms

Synonyms and Alternate Names:
Polygonum aequale Lindm.
Polygonum aviculare var. arenastrum (Jord. ex Boreau) Rouy
Polygonum montereyense Brenckle