[Fleeceflowers and Knotweeds: The Genus Polygonum West of the Cascade Mountains of Oregon and Washington]

Shasta knotweed (left) with Kellogg's knotweed (Polygonum polygaloides ssp. kelloggii) observed along the Pacific Crest Trail #2000 on the south side of Cook and Green Mountain in northern Siskiyou County, CA, Klamath National Forest......July 14, 2020.