Poa palustris L.

Loosely tufted, bright green perennial, to 80 cm, with flaccid leaves overtopped by culms; branching extravaginal at plant base, intravaginal above; leaf-blades persistent. Leaf-sheath light green to light brown, membranous, smooth, or scabrid above, distinctly ribbed, keeled near ligule. Ligule 1.5–3 mm, entire, oblong, slightly rounded and slightly short-ciliate, abaxially with sparse minute hairs. Leaf-blade 10–20 cm × 2–4 mm, flat, minutely scabrid throughout; tip acute. Culm 30–70 cm, erect, internodes glabrous, or rarely papillose and minutely pubescent just below nodes. Panicle 10–25 cm, very loose and open; rachis glabrous, branches delicate, finely scabrid, spreading and flexuous, naked below, branched above with few spikelets on each branchlet. Spikelets 3.5–5 mm, 3–4-flowered, light green tinged purple and brown. Glumes equal or subequal, 3-nerved, acute to acuminate, midnerve scabrid above; lower 2.3–2.8 mm, lanceolate, upper 2.5–3.2 mm, narrowly-ovate. Lemma 2.6–2.8 mm, 5-nerved but inner lateral nerves often obscure, oblong, obtuse, glabrous apart from fringe of short hairs to ½ length of midnerve and outer lateral nerves, scabrid on midnerve above hairs, sometimes purplish, with shining yellow-brown band above. Palea 2.3–2.6 mm, keels ciliate, interkeel glabrous. Callus with long tuft of soft crinkled hairs. Rachilla c. 0.5 mm, minutely scabrid; prolongation twice as long. Lodicules c. 0.4 mm. Anthers 0.7–1 mm. Caryopsis c. 1.3 × 0.5 mm.

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