Calflora
Taxon  Report   6734    
Polygonum amphibium  L.

(not an active name)

Swamp knotweed,   Water knotweed,   Water smartweed
Polygonum amphibium, a dicot, is a perennial herb that is native to California, and also found elsewhere in North America and beyond.
Siskiyou Del Norte Modoc Humboldt Shasta Lassen Trinity Plumas Tehama Butte Mendocino Glenn Sierra Yuba Lake Nevada Colusa Placer Sutter El Dorado Yolo Alpine Napa Sonoma Sacramento Mono Amador Solano Calaveras Tuolumne San Joaquin Marin Contra Costa Alameda Santa Cruz Mariposa Madera San Francisco San Mateo Merced Fresno Stanislaus Santa Clara Inyo San Benito Tulare Kings Monterey San Bernardino San Luis Obispo Kern Santa Barbara Ventura Los Angeles Riverside Orange San Diego Imperial

Bloom Period
Family: Polygonaceae  
Genus: Polygonum

Communities: Yellow Pine Forest, Red Fir Forest, Lodgepole Forest, Subalpine Forest, Foothill Woodland, Chaparral, Valley Grassland, wetland-riparian, many plant communities
Name Status:
Accepted by PLANTS

More information about  Polygonum amphibium

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2021. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 08/01/2021).