Plants annual, 6-25 dm; roots not also arising from proximal nodes; rhizomes and stolons absent. Stems erect, simple or branched distally, usually ribbed, strigose or glabrescent proximally, pilose to hirsute distally. Leaves: ocrea brownish proximally, green distally, narrowly funnelform, 10-20 mm, chartaceous proximally, foliaceous distally, rarely chartaceous throughout, base inflated or not, margins truncate, ciliate with bristles 1-3 mm, surface densely strigose to hispid, not glandular-punctate; petiole 1-8.5(-14) cm, densely pilose to hirsute; blade without dark triangular or lunate blotch adaxially, ovate, 6-25(-30) × 3-17 cm, base cordate to truncate, margins scabrous to ciliate, apex acuminate, faces minutely strigose to densely hirsute, especially along veins abaxially, not glandular-punctate. Inflorescences mostly terminal, nodding or erect, uninterrupted, 10-150 × 8-18 mm; peduncle 20-100 mm, hirsute; ocreolae overlapping, margins ciliate with bristles 0.2-1 mm. Pedicels ascending to spreading, 1-4 mm. Flowers (1-)2-5 per ocreate fascicle, homostylous; perianth roseate to red, glabrous, not glandular-punctate, slightly accrescent; tepals 5, connate in proximal 1/3, obovate, 3-4.5 mm, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 6-8, included or exserted; anthers pink or red, elliptic; styles 2, connate proximally. Achenes included, dark brown to black, discoid, 2.5-3.5 × 3-3.5 mm, shiny to dull, smooth to minutely granulate. Flowering Jun-Oct. Moist waste places; 0-500 m; introduced; N.B., Ont., Que.; Ala., Ark., Calif., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis.; s Asia (India). Persicaria orientalis was introduced as a garden ornamental. It often persists around homesteads and barnyards, and occasionally escapes and becomes weedy in moist waste places. A collection made in 1853 by F. V. Hayden at Fort Pierre, South Dakota (MO), is assumed to have come from a cultivated plant.
Erect, branching, pubescent annual to 2.5 m; lvs ovate, broadly rounded at base; ocreae villous, ciliate, often with a spreading, herbaceous collar; infl large; peduncles densely hairy; racemes commonly drooping, dense, cylindric, 3-8 cm, fls rose to crimson; achenes flat, lenticular, 2.8-3.5 mm, about as wide, beakless, smooth and shining; 2n=22, 24. Native of India, often escaped in waste places near gardens. (Persicaria o.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.