Calflora, a 501c3 non-profit
Distribution by County   6751    
Polygonum douglasii  Greene  ssp. johnstonii  (Munz) J. C. Hickman

(not an active name)

Johnston's knotweed,   Knotweed
Polygonum douglasii ssp. johnstonii is an annual herb that is native to California, and also found elsewhere in western North America.

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]. 2024. Berkeley, California: The Calflora Database [a non-profit organization]. Available:   (Accessed: 05/20/2024).