Polygonum ramosissimum
Bushy knotweed
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Family: Polygonaceae · Type: Herb · Native
Polygonum ramosissimum (Bushy knotweed) is a native California herb in the Polygonaceae family, recognized by no specific range data but appears to have no sympatric congeners.
Bushy knotweed is a California native annual found in various bioregions on open, disturbed sites at low to moderate elevations. Flowering from July to September, this plant produces tiny green-yellow to white or pink flowers clustered in spike-like inflorescences. Growing with erect, profusely branched stems 30 to 100 centimeters tall, it develops a green, ribbed structure with branches most dense in the upper half. Its narrow leaves range from 8 to 70 millimeters long, appearing light yellow-green to blue-green with elliptic or lance-shaped blades and acute tips. The small fruits are dark brown, shiny or dull, and typically 2 to 3.5 millimeters long.
Identification and appearance
Key characters: Geographically isolated; no specific range data but appears to have no sympatric congeners
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 ramosissimum native to California?
Yes. Polygonum ramosissimum is native to California (recorded as native).
What plant family does Polygonum ramosissimum belong to?
Polygonum ramosissimum is in the Polygonaceae family, genus Polygonum.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.