Gynodioecious shrub, up to c. 2 m tall. Branches erect; old stems grey; youngest branchlets olive-green, or red-brown; internodes (1-)4-13(-24) mm long; leaf decurrencies evident (usually weakly), or obscure; leaf-base scars evident; stem pubescence absent or bifarious, eglandular puberulent (when hairy). Leaf bud about as long as mature leaves with leaves of a pair separating when mature; sinus absent. Leaves decussate, free at base, spreading to recurved; lamina linear or linear-lanceolate or lanceolate or elliptic (especially var. oliveri or some North Island populations of var. stenophylla), subcoriaceous, folded or flat, (11-)23-53(-87) mm long, 2.5-6.5(-10) mm wide; apex acute; base cuneate; evident venation in fresh leaves consisting of midrib only or consisting of midrib and 2 secondary laterals arising from base; midrib slightly thickened beneath and depressed to grooved above; margin thickened, green, bevelled, mostly glabrous but occasionally pubescent, entire; adaxial surface green, dull, with few stomata or with moderately dense stomata, sparsely pitted (often only along margins) to conspicuously pitted with small depressions that each contain a twin-headed glandular hair, hairy along midrib; abaxial surface green, dull, with dense stomata (often many more than adaxial surface), conspicuously pitted with small depressions that each contain a twin-headed glandular hair. Inflorescences with (35-)55-130(-170) flowers, lateral, racemose and unbranched, (2.5-)4.5-6.5(-9.5) cm long, longer than subtending leaves, flowers generally opening in acropetal sequence; peduncle (0.5-)1-1.5(-2.1) cm long, eglandular pubescent; rachis (2-)4.5-6(-9) cm long, pubescent; bracts alternate, acute (mostly) or obtuse, eglandular ciliate or ciliate with both glandular and eglandular hairs, ovate or deltoid; pedicels ranging from much longer than bracts to equal to bracts, eglandular-pubescent or glabrous, erecto-patent to patent at anthesis, erecto-patent to patent or ascending at fruiting, (0.5-) 1-3(-5) mm long. Flowers protandrous, those on individual plants either hermaphrodite or female. Calyx 1.5-2.5 mm long, 4- lobed, equally divided; lobes all similar, ovate or oblong, obtuse to acute, eglandular ciliate (usually) or with mixed glandular and eglandular cilia (glandular hairs often with a single, rounded cell at the apex; twin-headed hairs, when present, usually sparse), margins membranous and sometimes tinged pink. Corolla white with lobes usually tinged mauve at anthesis, white after pollination; tube glabrous (usually) or hairy inside (especially var. hesperia), (1.8-)3-4.9 mm long, 1.3-2 mm wide, contracted at base and cylindric or expanded in lower half, longer than calyx; lobes glabrous, shorter than corolla tube; posterior lobe broad-ovate or circular, obtuse or slightly emarginate, suberect to recurved (mostly patent), with margin and apex turned upwards; lateral lobes usually broadly ovate to elliptic, obtuse, suberect to patent, with margin and apex turned upwards; anterior lobe elliptic to ovate, obtuse, patent, with margin and apex turned upwards, sometimes enfolding style or not enfolding style; corolla throat white. Stamen filaments white, diverging after anthesis, incurved at apex in bud, becoming straight after anthesis, 2.5-3.5 mm long; anthers obtuse (sometimes +/- emarginate) or apiculate, magenta, 1-1.5 mm long. Nectarial disc glabrous. Ovary ovoid, glabrous, 0.8-0.9 mm long, 2-locular; ovules 4-10 per locule, marginal in one layer on a flattened placenta; style 3-7 mm long, 0.12-0.2 mm thick, glabrous, pink; stigma subcapitate or capitate, yellow at anthesis, 0.12-0.25 mm wide. Capsules latiseptate, acute or obtuse, dark brown, (2-)2.5- 3.5 mm long, (0.8-)1.5-3 mm thick, glabrous, septicidal split extending to base, loculicidal split extending ¼-¾-way to base.

Branchlets glabrous or bifariously to uniformly puberulent. Leaves linear, or lanceolate, or elliptic, 19-87 mm long, 2.5-6.5(-9.5) mm wide; adaxial surface conspicuously pitted to apparently smooth (except along margins), stomata sparse to dense; margins broad, glabrous or minutely hairy (especially toward the apex). Inflorescences 26-95 mm long. Corolla tube usually glabrous within, 3.0-4.9 mm long.

Branchlets bifariously to uniformly puberulent. Leaves oblong-elliptic, linear-lanceolate or lanceolate, (16-)25-45(-62) mm long, (3.5-)4.0-8.0 mm wide; adaxial surface usually smooth, mostly pitted only toward the margin but sometimes with obvious pits toward middle of lamina, stomata sparse except at apex and sometimes along either side of midrib; margins broad, glabrous or with very fine hairs toward the apex. Inflorescences 32-64 mm long. Corolla tube hairy within, 1.8-3.0(-3.5) mm long.

Varietas Hebis stenophyllae, a varietatibus aliis characteribus secundis combinatis differt: ramulis uniformiter vel bifariam puberulis; paginis foliorum adaxialibus stomatibus et pilis glanduliferis depressis paucis; tubo corollae intra puberulo, 1.8-3.0(-3.5) mm longo.

Branchlets glabrous or bifariously puberulent. Leaves lanceolate or elliptic, 22-37 mm long, 5-10 mm wide; adaxial surface mostly smooth, not conspicuously pitted except toward margins, stomata sparse except near apex; margins broad, glabrous or with very fine hairs. Inflorescences 26-60 mm long. Corolla tube glabrous within, 2.5-3.8 mm long.

Varietas Hebis stenophyllae, a varietatibus aliis characteribus secundis combinatis differt: foliis lanceolatis vel ellipticis, 22-37 mm longis, 5-10 mm latis; paginis foliorum adaxialibus stomatibus et pilis glanduliferis depressis paucis; tubo corollae intra glabro, 2.5-3.8 mm longo.