Vascular Plants of North Carolina
Account for Pleatleaf Knotweed - Polygonum tenue (= Duravia species 2)  
Members of Polygonum with account distribution info or public map:
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Section 6 » Family Polygonaceae
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DistributionThis taxon is what most references have called Polygonum tenue; however, Weakley (2018) has it moved to a different genus. See Taxonomic Comments below. Scattered over the mountains and Piedmont; scarce in the southern half of the Piedmont.

ME to Ont., MN, and WY, south to GA, MS, TX.
AbundanceUncommon in the mountains; rare to uncommon and somewhat local in the Piedmont, except for rare in the southeastern parts of the Piedmont. This is a Watch List species.
HabitatDry, rocky or gravelly soil of glades, flatrocks, rock outcrops, woodland openings, ridgetops. On a variety of rock substrates, including mafic, shale, granite -- but always where the soil is dry and very thin (with rock close to the surface).
See also Habitat Account for General Dry-Xeric Glades and Barrens
PhenologyFlowering and fruiting July-October.
IdentificationPleatleaf Knotweed is immediately recognizable by the erect stems 8 inches to 1.5 feet tall, strongly ascending branches, the whole plant being slender and wiry. Leaves are short, linear, sharply pointed, and are folded lengthwise on each side of the midvein. As with other knotweeds, the flowers (cream-colored to whitish) are quite small and are found in the leaf axils. None of our other knotweeds look like it -- though P. prolificum, which grows mostly in damp ground, is somewhat a much larger version of it
Taxonomic CommentsGeneticists have placed it into the genus Duravia, but a replacement species epithet must be selected, not yet described. Weakley (2018) ascribed the #2 to the genus name -- Duravia species 2 -- though not stating why #2 was chosen.

Other Common Name(s)Slender Knotweed (used mainly for Persicaria decipiens), Glade Knotweed
State RankS2? [S2S3]
Global RankG5
State StatusW7 [W1]
US Status
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Thomas ReedTurnipseed Road powerline clearing, Wake County; 22 September 2020; ID by Harry LeGrand WakePhoto_natural
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