[Knotweeds and Smartweeds: The Genus Polygonum in the Columbia River Gorge]

California Knotweed

Polygonum californicum

Synonym: Polygonum greenii

California Knotweed: Polygonum californicum (Synonyms: Polygonum greenii)

California knotweed growing on crushed rock along an old road at Catherine Creek, Columbia River Gorge...................June 23, 2010.

Close-up of the inflorescence of California Knotweed: Polygonum californicum (Synonyms: Polygonum greenii) - Close-up of the inflorescence of California Knotweed: Polygonum californicum (Synonyms: Polygonum greenii)

California Knotweed: Polygonum californicum (Synonyms: Polygonum greenii) - California Knotweed: Polygonum californicum (Synonyms: Polygonum greenii)

Additional close-up photos of California knotweed growing on crushed rock along an old road at Catherine Creek, Columbia River Gorge...................June 23, 2010. On the photos which show close-ups of the inflorescence, note that the outer and inner tepals are about equal in size and shape and the segments of the stipules that subtend each leaf (and axillary flower) are rigid, straight and stiffly erect. The stipules tend to be a translucent white and as mentioned are deeply lacerate.

Paul Slichter