Perennial herb, caespitose, with many leaves forming a small, compact rosette. Leaves pinnatisect, up to 40(–50) mm long, glabrous, green, ± coriaceous; petiole 8–12 mm long, 1.7–1.8 mm wide, winged and sheathing at base. Terminal pinna 3.5–4.7 × 3.5–4.1 mm, with 2 conspicuous lateral lobes; lateral pinnae with 11–15 leaflets, in pairs and usually overlapping in distal part of leaf, alternate and distant in lower part of leaf, reniform, orbicular to broadly elliptic, hydathodes prominent on margin and in axil of petiolule, margin entire; base cordate, ± truncate to obtuse; apex obtuse to rounded. Lateral pinnae 1.5–2.5 × 0.7–2.2 mm; petiolules up to 0.5 mm long, often ± absent. Cauline leaves occasionally present subtending only the lower 1–2 flowers; similar to rosette leaves, but with fewer leaflets and smaller in all parts. Inflorescence usually up to 50 mm long, occ. 145 mm in sheltered sites, 1.2–1.6 mm diam. at base, glabrous, compact and not elongating after flowering, fastigiate, racemose, flowers usually crowded in upper half. Pedicels 5–10(–17) mm long, 0.8–1.2 mm diam., usually erect. Sepals 2.0–2.4 × 0.7–1.2 mm, oblong to elliptic, glabrous, margin white and membranous, apex obtuse to rounded, base truncate. Petals 3.2–4.0 × 1.2–1.5 mm, white, pale pink or purple, limb obovate; apex obtuse to rounded; base cuneate to attenuate, tapering to an indistinct claw. Stamens 6; median filaments 4, 1.6–2.0 mm long; lateral filaments 2, 1.1–1.4 mm long; anthers 0.4–0.5 mm long. Ovary 1.5–2.6 mm long, 0.5–0.6 mm diam., terete, glabrous; stigma 0.3–0.5 mm diam. Siliques 12–23 × 1.7–2.2 mm, glabrous, crowded, erect, style 0.7–1.4 mm long; replum 0.9–1.1 mm wide. Seeds 1.4–2.1 mm long, 1.1–1.5 mm wide, 0.4–0.5 mm thick, orbicular to broadly oblong, red-brown; wing absent.
Cardamine latior grows among boulders and fellfield, particularly at higher altitudes on mountaintop screes (Johnson & Campbell 1975).
Cardamine latior is assessed as having a conservation status of At Risk–Naturally Uncommon, with the qualifiers Data Poor, Island Endemic and One Location (de Lange et al. 2018). The qualifier Data Poor is applied because data are required on the number and size of the populations.
Flowering October–December; Fruiting October–February.