Juncus acutus L.

Very stout, forming dense prickly tufts; rhizomes stout, woody. Stems (40)–60–100cm × 1.5–5 mm, very stiff and erect, smooth, light green. Basal sheaths shining dark red-brown. Leaves 1–2, basal, terete, similar to stem, with very pungent tip. Inflorescence large, compact 5–15 cm long. Flowers crowded. Tepals c. 3 mm long, ± equal, very hard, outer mucronate, inner truncate to emarginate with wide membranous margin at tip. Stamens 6. Capsule 4.5–5 mm long, much > tepals, ovoid, abruptly tapered, acute, reddish-brown to brownish-orange. Seeds with distinct tails.

[From: Healy and Edgar (1980) Flora of New Zealand. Volume 3.]