Trisetum arduanum Edgar & A.P.Druce

Open tufts to 60 cm, erect or often drooping, with slender pale yellow-green to glaucous leaves and whitish open panicles; branching extravaginal. Leaf-sheath to 6 cm, glabrous, or with fine, very minute prickle-teeth, to minutely puberulous. Collar hairs few, long. Ligule 0.2–0.3 mm, truncate, slightly erose, glabrous, or rarely sparsely minutely ciliate. Leaf-blade 10–20–(30) cm × 0.5–1.5–(4) mm, usually narrow and inrolled, sometimes flat, abaxially smooth or with sparse to dense prickle-teeth towards tip, rarely throughout, adaxially ± shallowly ribbed, sparsely minutely prickle-toothed or sparsely pubescent on ribs; margins minutely prickle-toothed. Culm 6–35 cm, internodes glabrous, occasionally with a few short hairs above basal nodes, sometimes with a few minute prickle-teeth below panicle. Panicle (3)–8–18–(27) × 0.7–3.5–(5) cm, oblong-lanceolate, becoming lax with spreading branches but spikelets clustered and individually inconspicuous; rachis, branches, and pedicels with sparse to dense fine prickle-teeth, or rachis smooth below. Spikelets (4.5)–5–7–(7.5) mm, whitish or pale straw-coloured, sometimes purple-tinged. Glumes unequal, hyaline, keels minutely prickle-toothed in upper ½; lower ⅔-⅘ length of upper, linear-lanceolate, upper slightly < spikelet, elliptic-lanceolate; margins entire, or with a few minute prickle-teeth near acuminate tip. Lemma 4.5–6 mm, bicuspid, papillose; awn 3.5–8 mm, straight to later recurved, insertion in upper ¼ of lemma. Palea with minute prickle-teeth on keels and rarely on margins. Callus hairs to 0.5 mm. Rachilla hairs to 2 mm. Lodicules to 1 mm, glabrous. Anthers 1.2–2 mm. Gynoecium: ovary to 1 mm; stigma-styles to 1.3 mm. Caryopsis c. 2.6 × 0.6 mm.

[From: Edgar and Connor (2000) Flora of New Zealand. Volume 5 (second printing).]