Taxon  Report   6751    
Polygonum douglasii  Greene  ssp. johnstonii  (Munz) J. C. Hickman  
(no longer an active name)
Johnston's knotweed,  Knotweed
Polygonum douglasii ssp. johnstonii, a dicot, is an annual herb that is native to California, is also found outside of California, but is confined to western North America.
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
Genus: Polygonum
Parent: Polygonum douglasii

Wetlands: Occurs usually in non wetlands, occasionally in wetlands
Name Status:
Accepted by PLANTS

JEF other name:
Polygonum sawatchense ssp. sawatchense

Alternate Names:
PLANTS: Polygonum douglasii var. johnstonii
PLANTS: Polygonum sawatchense ssp. oblivium
PLANTS: Polygonum sawatchense
. . .
NOTE: Polygonum douglasii ssp. johnstonii is no longer an active name.
More information about  Polygonum douglasii ssp. johnstonii

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]. 2020. Berkeley, California: The Calflora Database [a non-profit organization]. Available:   (Accessed: Sep 29, 2020).