Phalaris paradoxa L.

Annuals, 20–80 cm. Leaf-sheath firm with narrow hyaline margin, ribs many, ± finely scabrid; uppermost sheaths conspicuously inflated, glabrous. Ligule 2–4–(6) mm, ± tapered. Leaf-blade 6–20 cm × 3–5.5 mm, tapered, ribs and margins finely scabrid, tip fine, soft, acute. Culm 14–56 cm, branched at base. Panicle 2.5–6 × 0.8–1.5 cm, cylindric, oblong, or widened above; rachis and very short branches scabrid, hidden. Spikelets in groups of 5–7–(9), with one central almost sessile ☿ spikelet 5–6.5 mm, surrounded by an involucre-like cluster of shorter, unequal, usually Ø, sometimes ♂ spikelets on short glabrous pedicels, two of the Ø spikelets generally larger. Glumes of all spikelets hard, keel sparsely scabrid, wing margin minutely scabrid; glumes of Ø spikelets sometimes sparsely hairy, margins scabrid in upper ⅓, apex rounded or truncate, or occasionally with acute flange; glumes of ☿ spikelets with 2–6 prominent lateral nerves and often shorter nerves as well, tapering above to acute tip, narrowly winged apart from an acute projecting middorsal flange. Ø florets: lemmas minute, scale-like, equal, glabrous. ☿ floret: lemma 2.9–3.3 mm, ovate, acute, almost glabrous; palea entirely glabrous or internerve sometimes sparsely hairy; anthers 1–1.6 mm; caryopsis 2–2.6 × 1.2–1.5 mm.

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