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

Reynoutria sachalinensis (F. Schmidt ) Ronse Decraene
giant knotweed
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants

Distribution of Reynoutria sachalinensis
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Species Information

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Illustration Source: The Illustrated Flora of British Columbia

General:
Perennial herb from a rhizome; stems erect, numerous, branched, 2-4 m tall, reddish, hollow.

Leaves:
Basal leaves lacking; stem leaves alternate, 10-30 cm long, the blades widely egg-shaped, the bases heart-shaped, the tips gradually tapered, long stalked; stipules tubular, entire.

Flowers:
Flowers in small axillary panicles; perianths 2-3 mm long, pale green or greenish-white, unequally 5-lobed, the outer lobes strongly winged.

Fruits:
Achenes, 3-angled, about 3 mm long, black, smooth and shiny.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Mesic fields, roadsides and waste places in the lowland zone; infrequent on Vancouver Island, the Gulf Islands and the Vancouver area, rare on the midcoast (Prince Rupert); introduced from Asia.

Source: The Illustrated Flora of British Columbia

Status Information

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Exotic	SNA	Exotic	Not Listed

BC Ministry of Environment: BC Species and Ecosystems Explorer, the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Fallopia sachalinensis

Taxonomic and Nomenclatural Links

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

Additional Range and Status Information Links

Burke Museum of Natural History (Washington State records)
CalFlora
Consortium of Pacific Northwest Herbaria records
Jepson Interchange
NatureServe Explorer

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: 2024-05-02 2:47:46 PM ]

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