Perennial; stems erect, square, scabrid, to 2 m tall. Lvs sessile, 5–7 × 1–1.5 cm (probably much larger on vegetative shoots), lanceolate or elliptic-lanceolate, strigose on both sides with bulbous-based hairs above, coarsely serrate; veins impressed; base ± attenuate with no distinct petiole; apex short-acuminate. Infl. much-branched, composed of spikes; spikes closely packed, 1–5 cm long at maximum flowering, not elongating much at fruiting, fairly stout; rachises scabrid; fls dense. Bracts slightly > calyx, linear to lanceolate, acuminate, hairy, ciliate, keeled. Calyx 2–3 mm long, with appressed hairs; teeth subulate, probably purple. Corolla with scattered hairs outside; tube slightly > calyx; limb 2–3 mm diam., mauve or purple, drying deep blue. Nutlets 1–1.5 mm long, oblong-obovoid, white-papillate on flattened ventral surface, wrinkled on dorsal surface, longitudinally ribbed.
[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]