Sporobolus alterniflorus (Loisel.) P.M.Peterson & Saarela

Robust perennials, (20)–50–100–(200) cm, with thick fleshy far-creeping rhizomes, forming rather open clumps. Leaf-sheath ± glabrous; cross-veinlets scattered, minute; margins often minutely ciliate below ligule. Ligule 1–2 mm, densely ciliate. Leaf-blade 8–45 cm × 6–15 mm, persistent, coriaceous, flat, glabrous, adaxially ribbed, much narrowed to fine hard tip. Culm erect, 8–30 mm diam. near base including closely ensheathing leaves. Panicles in N.Z. usually not developed, this description is from the two floriferous specimens seen: panicle c. 25 cm, erect, contracted; spikes 7–14, 5–7 cm; rachis of each spike glabrous, tipped by bristle 10–12 mm. Spikelets 14–17 mm, lanceolate, 1-flowered. Glumes very unequal, lanceolate, glabrous, subacute; lower slightly > ½ length of upper and much narrower, 1–3-nerved, upper = spikelet, 5–9-nerved. Lemma ≤ upper glume, 3–5-nerved, lanceolate, glabrous. Palea ≥ lemma, hyaline, glabrous. Anthers 3.5–6 mm. Caryopsis not seen.

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