Flora of the Southeastern United States

*Persicaria posumbu (Buchanan-Hamilton ex D. Don) H. Gross. Common name: Asian Lady's-thumb, Creeping Himalayan Smartweed. Phenology: Aug-Oct. Habitat: Floodplains, other moist shaded forests. Distribution: Native of e. Asia.

ID notes: "Persicaria posumbu can be distinguished from all other North American Persicaria by the following suite of traits: Low annual; eglandular; stems branched near the base, glabrous; ocreae strigose with terminal bristles 3-7 mm long; leaf blades elliptic, bases rounded and abruptly cuneate, the apices distinctly caudate, margins ciliate with bristles ca. 0.5 mm long, abaxial and adaxial surfaces strigose, bright green, adaxial surface with a prominent lunate purple blotch at maturity; inflorescences mostly terminal, lax, up to 15 cm long (including the peduncle), fascicles usually 3-flowered; bracteoles (ocreoleae) with terminal bristles ca 1 mm long, about as long as the exserted pedicels; tepals light pink to white, many opening to expose the barely exserted, white stamens; achenes all trigonous, 2.3-2.5 mm long and 1.5 mm wide, dark brown, lustrous" (Atha & Rall 2020).

Origin/Endemic status: E. and se. Asia

Synonymy ⓘ: = Il, K4, Atha & Rall (2020); = n/a — C, FNA5, Pa. Basionym: Polygonum posumbu Buch.-Ham. ex D. Don 1825

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Wetland Indicator Status:

• Eastern Mountains and Piedmont: FACU
• Northcentral & Northeast: FACU