Calamagrostis arenaria (L.) Roth

Long-rhizomatous, wiry-leaved perennials forming compact, glaucous-grey tufts to 170 cm; with strong woody rhizomes and numerous fibrous roots; branching intravaginal. Leaf-sheath glabrous, light straw-brown or brownish purple. Ligule 15–30 mm, membranous, narrowed to a point, abaxially covered with very minute hairs. Leaf-blade 35–60 cm ×c. 1.5 mm diam., tightly involute, abaxially glabrous, adaxially ribbed, ribs densely short stiff hairy. Culm 70–145 cm, internodes usually scabrid, sometimes smooth to slightly scabrid. Panicle 15–25–(35.5) cm, spike-like, cylindric, tapering above, with numerous crowded light green spikelets; rachis minutely scabrid, erect branches and pedicels hidden among spikelets. Glumes 9.5–14 mm, ± equal, persistent, subhyaline, narrow-lanceolate, glabrous, keel and margins minutely scabrid, tip blunt or obtuse; lower usually 1-nerved, upper usually 3-nerved. Lemma 8.5–13 mm, < glumes, 5-nerved, narrow-lanceolate, obtuse, minutely apiculate, keeled, keel minutely scabrid. Palea 2–4-nerved, subhyaline, central nerves minutely scabrid. Lodicules 1.5–2.5 mm. Callus ringed by long straight silky hairs. Rachilla prolongation bearing long, straight, silky hairs. Anthers 3.5–5.5 mm. Caryopsis c. 3 mm.

[From: Edgar and Connor (2000) Flora of New Zealand. Volume 5 (second printing) as Ammophila arenaria (L.) Link.]