Cardamine thalassica Heenan

Perennial herb, single rosette or with lateral branches. Leaves up to 135 mm long, pinnatisect; lamina 17.0–65.0 × 16.0–42.0 mm, grey to grey-green, coriaceous, glabrous; petiole up to 92 mm long. Terminal pinna 5.7–14.0 × 4.5–9.5 mm, simple, broadly elliptic, elliptic-orbicular, ovate or broadly ovate; margin entire; lateral hydathodes absent; apex obtuse with a distinct hydathode; base obtuse. Lateral pinnae 2–6, 4.4–13.0 × 3.0–9.5, simple, broadly elliptic, elliptic-orbicular, ovate or broadly ovate; margin entire, lateral hydathodes absent; apex obtuse with a distinct hydathode; base obtuse; petiolule 1.8–10.5 mm long. Cauline leaves similar to rosette leaves but smaller, narrower, with fewer lateral pinnae, pinnae bases attenuate to cuneate; terminal pinna up to 20.0 × 5.0 mm, lateral pinnae up to 12.0 × 5.7 mm. Inflorescence racemose, sometimes with lateral racemes, each raceme 6–18‑flowered; peduncle up to 250 mm long, 1.2–1.6 mm diam. at base, ascending, glabrous. Pedicels 10.0–22.0 mm long, 0.4–0.5 mm diam., glabrous. Sepals 2.1–2.4 × 0.8–1.4 mm, elliptic-oblong, saccate, green to red-brown, glabrous, margin white and membranous, apex obtuse, base truncate. Petals 3.6–4.5 × 1.2–1.4 mm, white, limb obovate; apex obtuse; base attenuate, tapering to a 1.0–1.5 mm‑long claw. Stamens 6; median filaments 4, 2.4–3.1 mm long; lateral filaments 2, 2.1–2.9 mm long; anthers 0.3–0.4 mm long, cream, when dehiscent held slightly below the stigma. Ovary 2.5–3.2 mm long, 0.4–0.6 mm diam., ± terete, green-brown, glabrous; ovules 30–32; style c. 0.3 mm long, ± terete; stigma 0.4–0.5 mm diam. Siliques 21.0–34.0 × 1.1–1.3 mm, glabrous, style 0.7–1.0 mm long; valves green-brown at maturity and when dehiscent; replum 0.7–0.8 mm wide. Seeds 1.3–1.4 mm long, 0.8–0.9 mm wide, oblong to orbicular-oblong, yellow-brown; wing absent.

Cardamine thalassica is distinguished from C. glara by being entirely glabrous, with grey to grey-green leaves, leaflets with more distinct petiolules, inflorescence a raceme, shorter petals, and longer seeds.

Cardamine thalassica grows on dry, unstable, bouldery colluvium and rocky slopes.

Flowering December–March; Fruiting December–March.