*Persicaria posumbu (Buchanan-Hamilton ex D. Don) H. Gross. Section: Persicaria. Phen: Aug-Oct. Hab: Floodplains, other moist shaded forests. Dist: 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, K3, K4, Atha & Rall (2020); = n/a – C, FNA5, Pa