2n = c. 63

Tufts erect, weakly caespitose to caespitose, slender; rhizomes short, ascending, and slender, culms bulbous at base. Leaves 200-400(-600) × 1.8-3.2 mm, soft, ascending, double-folded, green to verdant-green; margin scabrid, weakly rasping but not harsh; keel on abaxial face glabrous, keels of the folds on adaxial face weakly scabrid. Culms 150-400(-920) × 0.5- 1.2 mm, erect, glabrous in lower part, glabrous or weakly scabrid in upper part, trigonous, shorter or longer than the leaves when mature; basal sheaths to 20 mm long, pale brown to straw coloured, nerves distinct. Inflorescence spikes 3-5, to 40 mm long and 3—4 mm wide, erect; upper spikes ± approximate, lower l(-2) spikes distant; peduncles 2-5(-25) mm long; spikes subtended by narrow leaf-like bracts much longer than the spikes; terminal spike male, often with a few female florets in proximal part, female spikes slender and with 10-60 florets, florets overlapping but not crowded. Glumes 1.5—2.0 × 1.4- 2.0 mm, much shorter than utricles, glumes ovate, oblong, light green to pale brown, membranous, deciduous, with two lobes at apex, midrib light green to pale brown; awn 0.5-1.5 mm long, scabrid. Utricles 3.0-4.0 × 1.4-1.5 mm, narrow ovoid, elliptic, plano-convex or subtrigonous, pale green to olive green when immature, usually pale brown or purple brown when mature, surface usually distinctly reticulate when dry (× 20 magnification), nerves pale and distinct, margins smooth; beak 0.5-0.7 mm long, pale, margin entire, crura 0.2-0.3 mm long; stipe 0.3-0.4 mm long. Stigmas 3. Nut 2.4-2.5 × 1.1- 1.3 mm, trigonous, ovoid, dark brown to grey brown, crowned with persistent style base. FL Jul-Jun; FT Jul-Jun.

A Carice spinirostri Colenso differt culmis basi tumidis angustioribus, foliis prasinis angustioribusque, spicis erectis, utriculis immaturis uniformiter olivaceis purpureo-brunneis maturescentibus. Habitat solum in substrata ophiolithico.