[Knotweeds: The Genera Bistorta, Fallopia, Persicaria and Polygonum in the Columbia River Gorge of Oregon and Washington]

Douglas' Knotweed, Austin's Knotweed

Polygonum douglasii

Synonyms: Polygonum douglasii ssp. douglasii, Polygonum douglasii var. douglasii, Polygonum douglasii var. latifolium, Polygonum montanum

Douglas' Knotweed: Polygonum douglasii (Synonyms: Polygonum douglasii ssp. douglasii, Polygonum douglasii var. douglasii, Polygonum douglasii var. latifolium, Polygonum montanum)

Douglas' knotweed is generally a slender, erect species with several narrowly oblanceolate stem leaves. The flowers are axillary.
Paul Slichter