Section 6 » Family Polygonaceae |
Show/Hide Synonym
taxonName | relationship | relatedTaxonName | relatedTaxonRefText | relComments |
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Duravia species 2 | = | Polygonum tenue | Gleason and Cronquist (1991) | | Duravia species 2 | = | Polygonum tenue | Flora of North America (1993b, 1997, 2000, 2002a, 2002b, 2003a, 2004b, 2005, 2006a, 2006b, 2006c, 2007a, 2009, 2010) | | Duravia species 2 | = | Polygonum tenue | | | Duravia species 2 | = | Polygonum tenue | | | Duravia species 2 | = | Polygonum tenue | Radford, Ahles, and Bell (1968) | | Duravia species 2 | = | Polygonum tenue | Small (1933, 1938) | | Duravia species 2 | = | Polygonum tenue | | | Duravia species 2 | = | Polygonum tenue | Flora of Virginia | | Duravia species 2 | = | Polygonum tenue | Wofford (1989) | | Duravia species 2 | = | Polygonum tenue | Flora of West Virginia | | Duravia species 2 | = | Polygonum tenue | | | Duravia species 2 | = | Polygonum tenue | | | Duravia species 2 | > | Polygonum tenue var. protrusum | Fernald (1950) | | Duravia species 2 | > | Polygonum tenue var. protrusum | Gleason (1952) | | Duravia species 2 | > | Polygonum tenue var. protrusum | | | Duravia species 2 | > | Polygonum tenue var. tenue | Fernald (1950) | | Duravia species 2 | > | Polygonum tenue var. tenue | Gleason (1952) | | Duravia species 2 | > | Polygonum tenue var. tenue | | | Source: Weakley's Flora |
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Distribution | This 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. | |
Abundance | Uncommon 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. | |
Habitat | Dry, 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). |
Phenology | Flowering and fruiting July-October. | |
Identification | Pleatleaf 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 Comments | Geneticists 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. The editors are strongly annoyed that a well-known, long-term species is suddenly not given a scientific name, for several years now.
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Other Common Name(s) | Slender Knotweed (used mainly for Persicaria decipiens), Glade Knotweed | |
State Rank | S2S3 | |
Global Rank | G5 | |
State Status | W7 [W1] | |
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