Cardamine coronata Heenan

Perennial herb, single rosette or with short lateral branches, stem and branches 0.5–1.4 mm diam. Leaves up to 140 mm long, pinnatisect; lamina 25.0–75.0 × 15.0–40.0 mm, light green to green, usually coriaceous, sparsely to moderately hairy on adaxial surface and margin, glabrous or sparsely hairy on abaxial surface and petiole; hydathodes on leaflet margin, conspicuous, usually with apical protuberance up to 0.2 mm long and 0–5 hairs up to 0.6 mm long; hydathode in leaflet axil, up to 0.3 mm long; petiole up to 70 mm long. Terminal pinna 10.0–20.0 × 12.0–26.0 mm, usually shallowly lobed, broadly orbicular, broadly orbicular-reniform, apex obtuse, base truncate to occasionally weakly cordate. Lateral pinnae 2–8, 5.0–13.0 × 5.0–18.0, broadly orbicular, orbicular-rhomboid to reniform-rhomboid, petiolule 3.0–20.0 mm long. Cauline leaves similar to rosette leaves but smaller, with fewer lateral pinnae, and leaflet lobes becoming angular. Inflorescence racemose, with lateral racemes, each raceme 6–12-flowered, flowers positioned toward apex; peduncle up to 400 mm long, 1.0–2.0 mm diam. at base, erect, glabrous. Pedicels 3.0–15.0 mm long, 0.4–0.7 mm diam., terete, glabrous. Sepals 2.4–3.2 × 1.1–1.3 mm, elliptic-oblong to elliptic, ± saccate, green, glabrous or sparsely hairy, margin white and membranous, apex obtuse, base truncate. Petals 4.5–8.0 × 2.5–3.6 mm, white, limb obovate; apex obtuse; base cuneate, tapering to a 1.0–2.0 mm long claw. Stamens 6; median filaments 4, 2.5–4.0 mm long; lateral filaments 2, 1.8–3.4 mm long; anthers 0.5–0.6 mm long, maroon or yellow, when dehiscent held at a similar height to or slightly below the stigma. Ovary 2.4–5.0 mm long, 0.6–0.7 mm diam., ± terete, green, glabrous or rarely hairy; ovules 18–20; style 0.6–1.6 mm long, ± terete; stigma 0.5–0.6 mm diam. Siliques 25.0–38.0 × 1.1–1.4 mm, glabrous or occasionally hairy, style 1.5–2.5 mm long; valves green at maturity; red-brown when dehiscent, replum 1.1–1.2 mm wide. Seeds 1.2–1.8 mm long, 0.6–0.9 mm wide, 0.4–0.5 mm thick, oblong to broadly oblong, light green to yellow-green; wing absent.

Cardamine coronata is similar to C. forsteri but differs from that species by its larger and more robust growth habit and leaves, leaflet margin and axillary hydathodes usually with additional hairs at the base, larger petals and sepals, longer filaments, and maroon anthers.

Cardamine coronata is known from the limestone ridge at Mt Cass, North Canterbury, and limestone at Castle Hill, Mid Canterbury. It usually occurs in sheltered sites on exposed limestone outcrops, and on limestone within the canopy of relatively open lowland forest and shrubland.

Flowering October–February; Fruiting December–March.