Vascular Plants of North Carolina
Account for Southern Jointweed - Polygonella americana   (Fischer & C.A. Meyer) Small
Members of Polygonaceae:
Members of Polygonella with account distribution info or public map:
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Section 6 » Order Polygonales » Family Polygonaceae
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Author(Fischer & C.A. Meyer) Small
DistributionSouthern part of the Sandhills only; not yet found in heavily covered Cumberland and Moore counties. Although all populations are ruderal, they are probably native and natural extensions of those in SC, where widespread.

Coastal Plain, NC to southern GA and TX; inland locally to TN, AR, OK, NM.
AbundanceRare, with a scattering of populations known, though populations may consist of dozens of plants. The NCNHP's State Rank of SU is unhelpful, and the website editors suggest S1S2. Some references and agencies consider this species as likely adventive and not native to NC, and the NCNHP even gives a State Rank of W4 -- perhaps or possibly not native. Weakley (2018) does consider it native in NC, as do the website editors, for reasons mentioned above. It appears to be scarce enough to list it as Significantly Rare.
HabitatXeric openings and disturbances (roadsides, mown or burned clearings, military drop zones) within Longleaf Pine sandhills.
PhenologyFlowering and fruiting mid June-October.
IdentificationSouthern Jointweed is rather robust and very showy in flower. Its thick stems grow 2-3 feet tall and have wide-spreading inflorescence branches that are covered with bright white flowers. Its leaves are small and hardly noticeable at any distance. No other NC plant looks like it, as the other members of the genus are much shorter and more slender.
Taxonomic CommentsA few recent authors have noted the genetic similarity of Polygonella to Polygonum and have lumped the two. Because the two can be easily told apart in the field, taxon editors, including Weakley (2018), prefer to recognize both genera. As mentioned above, the NCNHP uses the name of Polygonum pinicola.
Other Common Name(s)American Jointweed
State RankSU [S1S2]
Global RankG5
State StatusW4 [SR]
US Status
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B.A. SorrieScotland County, 2009, E side of US 15-501, shortly S of Drowning Creek. ScotlandPhoto_natural
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