Verbena bonariensis L.

Perennial; stems hairy or scabrid, erect, ± square, to c. 3 m tall. Lvs sessile, 3–17 × 1–6 cm, oblong-lanceolate to ovate, coarsely and irregularly toothed, strigose with bulbous-based hairs denser above than below; veins strongly impressed above; base usually amplexicaul, sometimes subcordate or cordate; apex acute. Infl. much-branched, densely hairy, composed of spikes; spikes closely packed, 0.8–3 cm long at maximum flowering, not elongating much at fruiting, rather stout; fls dense. Bracts ± = or slightly > calyx, lanceolate, hairy, keeled. Calyx c. 3 mm long, hairy, purple, ± glandular-scaly; teeth acuminate or acute, similar to bracts. Corolla tube nearly 2× length of calyx, hairy outside; limb 2–3 mm diam., mauve or purplish, often drying deep blue. Nutlets 1–1.5 mm long, oblong, brown on dorsal surface, longitudinally ribbed, white-papillate on flattened ventral surface.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]