[Knotweeds and Smartweeds: The Genus Persicaria and Polygonum in the Columbia River
Gorge of Oregon and Washington]
Common Knotweed, Doorweed, Oval-leaf Knotweed, Prostrate Knotweed, Yard Knotweed
Polygonum aviculare ssp. depressum
Synonym: Polygonum arenastrum
The photo above shows the prostrate stems of prostrate knotweed sprawling across the sand at the beach at the Dalles Riverside Park, Columbia River Gorge.........September 29, 2007. Note the paired, axillary flowers and alternate stem leaves.
The photo above shows the prostrate stems of prostrate knotweed sprawling across the sand at the beach at the Dalles Riverside Park, Columbia River Gorge.........September 29, 2007.
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Additional close-ups of
the leaves and flowers of prostrate knotweed as seen along road #82 at Snowking
Snowpark on the southern slopes of Mt. Adams.........October 2005. Note
that the outer and inner series of tepals in individual flowers are the same
length.
Prostrate knotweed still in bloom in the gravel in the road to Sheep Canyon and Greyback Mountain, Klickitat Wildlife Area.........October 9, 2017.
Prostrate knotweed sprawling across the rocky beach of the Deschutes River about one-half mile upstream from its mouth........July 27, 2011.
Paul Slichter