Veronica colensoi Hook.f.

Small, often spreading shrub to 0.75 m tall. Stems erect, glabrous or sparsely eglandular-pubescent; hairs bifarious. Leaf bud distinct, its outer leaves appressed at margins until fully grown; sinus acute. Leaves opposite-decussate to sub-distichous, erecto-patent, spreading with age; lamina coriaceous, narrowly to broadly elliptic or obovate, 10–42 mm long, 4–16 mm wide, dull and glaucous above and beneath; midrib evident; surfaces glabrous or eglandular-hairy along midrib above; margin minutely papillate, entire or shallowly toothed in up to 10 pairs; apex sub-acute to obtuse, usually weakly plicate-acuminate; base cuneate; petiole 1–2 mm, rarely to 3 mm long. Inflorescence a lateral, rarely terminal, raceme, sometimes the lower ones tripartite, rarely compound, 17–45 mm long; flowers crowded, 11–29, female or bisexual on separate plants, ⚥ ≥ ♀; bracts alternate, the lowest sometimes opposite, lanceolate to deltoid or oblong, ≥ pedicels; pedicels erect to erecto-patent, 0.5–3.0 mm long, eglandular-hairy all around, rarely glabrous. Calyx lobes 4 or  5^th lobe small, posterior; anterior lobes free or fused up to ⅔-way, 1.8–2.3 mm long, unequal, glabrous or rarely sparsely eglandular-ciliolate. Corolla 6–11 mm diameter; tube white, 1.8–2.5 mm long, slightly < to slightly > calyx, glabrous; lobes 4, white, erecto-patent to spreading, sub-equal, narrowly lanceolate to ovate, 2.5–3.5 mm long, acute to acuminate, sometimes tapering to obtuse tip; nectar guides absent. Stamen filaments white, 2.0–3.5 mm long; anthers yellow, buff, pink or pale purplish. Style glabrous, 2.2–4.5 mm long. Capsules latiseptate, acute, glabrous, 2.5–3.8 mm long, 1.9–2.5 mm at widest point. Seeds ellipsoid-oblong, flattened, smooth, pale brown or orange-brown, 1.1–1.5 mm long.

V. colensoi is characterised by calyx lobes that are glabrous even on their margins. This is a very unusual character state in Veronica, being seen sometimes in V. macrocalyx and V. pareora and some northern hemisphere herbaceous speedwells, such as the naturalised V. scutellata. Its glaucous leaves are unusual for a North Island hebe; the only other North Island hebe characterised by glaucous leaves is V. scopulorum. V. scopulorum is distinguished from V. colensoi by its somewhat discolorous leaves (green above and glaucous beneath), ciliolate calyx lobes, and longer corolla tube.

Rock outcrops, on bluffs, gorges, and river banks. Recorded elevations range from 500 to 1533 m.

Flowers: September–November (rarely August, December, January); fruits: December–April (persisting until October).

2n = 40 (see Bayly & Kellow 2006, as Hebe colensoi).

Veronica colensoi is classified in V. subg. Pseudoveronica sect. Hebe and the informal group “Apertae” (small-leaved) (Albach & Meudt 2010; Bayly & Kellow 2006). ITS sequence data suggest V. colensoi and V. scopulorum are sister species; this is supported by their close similarity and North Island distributions. Beyond that, their relationships are likely to be with other species that are characterised by glaucous leaves, all of which occur in the South Island, such as V. rigidula.

Elder (1940) included V. darwiniana Colenso in synonymy of V. colensoi, but Bayly & Kellow (2006)​​​​​​​ placed it incertae sedis.