Cardamine serpentina Heenan

Perennial rosette herb, stem and branches c. 2 mm diam. Leaves up to 40 mm long, simple or pinnatisect; lamina 3–13 × 3–8 mm, green-brown to purple-brown, coriaceous, glabrous; terminal pinna 2.0–6.0 × 1.8–8.0 mm, orbicular-reniform to deltoid-reniform, apex obtuse with a small but distinct hydathode; base truncate to cordate. Lateral pinnae 1–2 or absent, 0.8–3.2 × 0.8–2.3 mm, orbicular, petiolule up to 1.2 mm long; petiole up to 32 mm long, plano-convex, glabrous. Cauline leaves sometimes subtending lower pedicels, narrowly obovate, up to 13 mm long. Inflorescence corymbose to corymbose-racemose, with 1–3 lateral corymbs, each corymb 2–8-flowered, flowers sometimes solitary, peduncle up to 100 mm long, 0.6–0.9 mm diam. at base, upright, glabrous, green-brown to purple-brown. Pedicels up to 36 mm long, 0.3–0.5 mm diam., flexuose, ascending to divaricate. Sepals 1.8–2.4 × 1.0–1.8 mm, broadly oblong to ovate, weakly saccate, green, often flushed red-brown, glabrous, margin white and membranous, apex obtuse, base truncate. Petals 4.5–5.0 × 2.6–3.0 mm, white, limb obovate; apex obtuse; base attenuate, tapering into the ± indistinct claw. Stamens 6; median filaments 4, 2.7–3.1 mm long, lateral filaments 2, 2.9–3.5 mm long; anthers 0.6–0.7 mm long, yellow, overtopping the stigma. Ovary 2.7–3.2 mm long, 0.5–0.6 mm diam., ± terete, green, glabrous; ovules 13–14 in each locule; style 0.3–0.5 mm long, ± terete; stigma 0.3–0.4 mm diam. Siliques 12–20 × 0.9–1.2 mm, erect, glabrous, valves green-brown to purple-brown at maturity, style 0.8–1.8 mm long. Seeds 1.0–1.2 mm long, 0.8–0.9 mm wide, 0.3–0.4 mm thick, orbicular to orbicular-oblong, orange-brown; wing absent.

Cardamine serpentina is distinguished from C. glara by its smaller and compact growth habit, smaller green-brown to purple-brown leaves, smaller terminal leaflet with a more distinct cordate base, fewer lateral pinnae, smaller sepals, and shorter siliques.

Cardamine serpentina grows on scree and loose stones/rubble around outcrops derived from ultramafic rocks.

Flowering December–February; Fruiting December–April.

Previously known by the tag name C. “West Dome” (e.g., de Lange et al. 2013, p. 68).