Scientific Name:
Arundo donax L. (1753)
Vernacular Name(s):
giant reed

Large robust perennial clumps to 5 m, with very wide leaves, and stout, woody, thick and knotty rhizomes up to 3 cm diam. Leaf-sheath rounded, coriaceous, smooth and glabrous, long hairy at apex. Ligule 1–2 mm, truncate, short-ciliate, collar brownish with some long soft tangled hairs. Leaf-blade 30–60 × 2.5–5 cm, cordate at base, scabrid on margins and abaxially on the much-narrowed, long-tapered tip, otherwise smooth. Culm erect, internodes smooth. Panicle 30–50 cm, plume-like, very densely branched; branches obliquely ascending, scabrid from fine teeth. Spikelets 10–12 mm, 2–4-flowered, purplish later becoming brownish. Glumes ± equal, the lower including lemmas, 3-nerved, glabrous, lanceolate, acute to acuminate. Lemma 7–9 mm, 5–7-nerved, densely, soft long (c. 5 mm) hairy from below, lanceolate, tapered, lateral lobes 2, very short, awn-tipped, sinus with awn 2–3 mm, straight. Palea < lemma, apex ciliate, keels shortly densely ciliate. Callus sharp, small, glabrous, sparse hair tufts c. 1 mm. Rachilla and prolongation c. 2 mm, glabrous. Lodicules 2, c. 0.5 mm, cuneate, 3-nerved, glabrous, irregularly toothed. Anthers 2.5–3.5 mm. Gynoecium: ovary 0.5 mm, stigma-styles to 2 mm. Caryopsis not seen. Fig. 15.

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

Biosecurity New Zealand 2012: Regional Pest Management Strategies Database.
Biosecurity New Zealand 4 Aug 2011: Unwanted Organisms Register.
Biosecurity New Zealand 2008: National Plant Pest Accord. MAF Biosecurity New Zealand, Wellington.
Howell, C. 2008: Consolidated list of environmental weeds in New Zealand. DOC Research & Development Series 292: 42.
Ministry for Primary Industries 23 Feb 2017: Unwanted Organisms Register. Version 02.01.02.