Lepidium castellanum Lange, Heenan, Houliston, Rolfe & Mitchell 2013

(Figs 27–32). Tap-rooted, strongly pungent smelling, much-branched, leafy perennial shrub, up to 1.8 × 2.0 m. Tap-root up to 800 mm long, ± napiform and/or scarcely branched. Rootstock 6–10 mm diam., woody, exposed portion smooth. Stems persistent, arising from rootstock base and basal portion of main central stem, closely packed, woody, erect, weakly angled to ± terete, glabrous; mature stems 3.8–8.2 mm diam., 0.3–1.8 m long; red-green to yellow-green, brittle, bases bearing numerous leaf abscission scars otherwise mostly leafy from mid-stem to apex at flowering; middle stems dark green to red-green, fleshy and pliant, initially ± square, prominently angled, becoming ± terete with age. Leaves coriaceous, fleshy, green to dark green, rosette-leaves absent, stem leaves withering with age; basal stem leaves 88.5–120.0 × 14.5–30.0 mm, lamina broadly lanceolate to lanceolate, margin ± deeply and ± evenly incised, teeth in 50–90 ± equal pairs, 0.5–2.9 mm long, protruding beyond leaf line, narrowly deltoid, to deltoid, leaf apex truncate-praemorse often deeply lacerate, teeth 3–5, cut 2.4–4.2 mm to lamina, narrowly deltoid, to deltoid, often bidentate, leaf base attenuate extending into a broad petiole wing; petiole distinct, 23.6–31.0 × 3.1–3.3 mm, decurrent, channelled, often with a broadly sheathing base; upper stem leaves 50.0–68.0 × 4.4–12.2 mm, decreasing in size toward inflorescences, lamina narrowly lanceolate to linear-lanceolate, margin ± deeply and ± evenly incised, teeth in 6–14 widely and evenly spaced ± pairs, 1.5–7.2 mm long, protruding beyond leaf line, narrowly deltoid, tapering, acerose, ± acicular to acicular-falcate; lamina apex acute (rarely truncate-praemorse), acuminate, acumen 5.8–11.0 mm long, margins of acumen toothed, teeth often bidentate, 8–10 mm long, acerose, often acicular, or acicular-falcate, leaf base attenuate extending into a narrow petiole wing; petiole distinct, 2.9–8.2 × 1.2–3.3 mm, decurrent, channelled, often with a broadly sheathing base. Inflorescences racemose, 50–100 mm long at fruiting; rachis 0.5–2.25 mm diam., terminal and lateral, leaf-opposed, often long-persistent, sparsely to densely covered in pale, patent, ± clavate hairs or rarely glabrous, hairs 0.1–0.14 mm long; pedicels 5.6–7.2 mm long at fruiting, erecto-patent, with sparse, pale, patent, clavate hairs on adaxial surface, hairs 0.1–0.12 mm long. Flowers 3.0–4.5 mm diam., fragrant. Sepals 4, saccate, ± overlapping at base, lateral sepals broad, 0.5–1.5 mm diam., orbicular, pale to dark green with a broad white, ± undulose margin, apex rounded to obtuse, abaxial surface often hairy, hairs 0.2–0.4 mm long, eglandular or with glandular tip, mostly shedding at anthesis except near base, median sepals 0.5–0.9 mm diam., broadly elliptic, pale to dark green with a broad white, ± undulose margin, apex rounded to obtuse, abaxial surface glabrous. Petals white, 1.1–2.0 × 1.0–1.6 mm, spreading, claw 0.4–0.8 mm long; limb obovate, obovate-spathulate to orbicular, apex obtuse to rounded often slightly emarginate, margins smooth, sometimes weakly undulose. Stamens 4, filaments 1.2–2.0 mm long, white; anthers 0.3–0.5 mm long, yellow. Ovary 1.1–1.8 × 0.6–1.3 mm, ovate, broadly ovate to elliptic, green-brown, apex subacute; style 0.11–0.4 mm long, cylindrical; stigma 0.2–0.5 mm diam. Nectaries 4, 0.2–0.3 × 0.1–0.15 mm, narrow-oblong to deltoid, pale translucent green. Silicles cartilaginous when fresh, coriaceous when dry, 2.4–3.6 × 1.8–2.5 mm, elliptic to rhomboid, apex acute and tapering, valves green maturing grey-white, glabrous, scarcely separating at apex at maturity, not winged; style 0.3–0.7 mm long, exserted. Seeds 2, 1.3–1.9 × 0.8–1.6 mm, narrowly to broadly ovoid, brown to orange-brown, not winged. FL Jul–Jun. FR Sep–Jul.

(Fig. 15). Endemic. Kermadec Islands (Macauley Island, Curtis Island, Haszard Islet and Cheeseman Island).