Polygonum aviculare subsp. rurivagum
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Family: Polygonaceae · Type: Annual · Not Native
Polygonum aviculare subsp. rurivagum is a non-native California annual in the Polygonaceae family.
Prostrate knotweed is a naturalized annual found in California in disturbed places at elevations below 1,000 meters. Flowering from June to November, this plant produces small green flowers with pink to red margins. Growing with prostrate to ascending stems 10 to 40 centimeters long that branch at most nodes, it spreads widely across the ground. Its narrow elliptic leaves are 15 to 27 millimeters long, less than 5 millimeters wide, with acute tips and raised lateral veins. The fruit is black-brown, three-angled, and covered with coarse striations.
Habitat and range
Habitat: Disturbed places
Elevation: < 1000 m
Outside California: scattered in North America, native to Europe
Bloom period
Polygonum aviculare subsp. rurivagum blooms Jun-Nov.
How to tell it apart
vs Euphorbia: Polygonum has swollen stem joints with papery sheaths; Euphorbia has milky sap when broken.; vs Persicaria: Hold node sheaths to light—Polygonum's are translucent and split; Persicaria's are opaque and intact.; vs Eriogonum: Polygonum has papery sheaths at nodes; Eriogonum has flowers in cup-like involucres.; vs Acmispon: Polygonum has swollen stem nodes; Acmispon has compound leaves with 3-5 leaflets.; vs Atriplex: Polygonum has papery stem sheaths; Atriplex has mealy or scurfy coating on leaves.
Frequently asked questions
Is Polygonum aviculare subsp. rurivagum native to California?
No. Polygonum aviculare subsp. rurivagum is not native to California (recorded as not native).
When does Polygonum aviculare subsp. rurivagum bloom?
Polygonum aviculare subsp. rurivagum blooms Jun-Nov.
What plant family does Polygonum aviculare subsp. rurivagum belong to?
Polygonum aviculare subsp. rurivagum is in the Polygonaceae family, genus Polygonum.
What habitat does Polygonum aviculare subsp. rurivagum grow in?
Polygonum aviculare subsp. rurivagum grows in Disturbed places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.