Persicaria lapathifolia (L.) Delarbre

Annual; stems ± erect, to 1 m tall, glabrous, green or reddish, often with red spots below the ± swollen nodes; taproot moderately stout. Lvs on main stem similar to those on branches; petioles to 3 cm long. Lamina (2)–3–15–(20) × (0.5)–1–4.5–(7) cm, lanceolate to narrow-ovate, glandular-punctate and glabrate to whitish tomentose below (sometimes hairy only on midrib), often with dark blotch on upper side, entire, ciliate; base ± attenuate; apex obtuse or subacute. Ochreae to 1 cm long, initially green or pinkish, truncate; apex glabrous or ciliolate. Infl. to 4 cm long, erect, dense and cylindric, usually simple and uninterrupted, mostly terminal; pedicels short, obscured by ochrea-like bracts; peduncles sparsely to densely covered with subsessile yellow or cream glands. Perianth c. 2 mm long, sparsely to moderately glandular, somewhat accrescent, usually white, sometimes pink; veins prominent, forked and recurved (anchor-shaped); segments ± elliptic, imbricate. Nut 2.5–3 mm long, usually ± biconvex, occasionally trigonous with rounded edges, dark brown, shining.

[From: Webb et al. (1985) Flora of New Zealand. Volume 4 as Polygonum lapathifolium L.]