Juncus supiniformis Engelm.

Perennials, 3–50 cm tall, caespitose or matted, sometimes floating; rhizome short, ±vertical, densely branched, occasionally stoloniferous or with intravaginal shoots. Cataphylls 1–2 or absent, stramineous; basal leaves 1–3, 3.7–15 cm long. Cauline leaves 1–4, 3.7–15 cm long, terete, unitubular, perfectly septate; tip acute; sheath broadly bordered membranous, open, lax; auricles 0.8–2.1 mm long, rounded to acute, membranous; occasionally leaves floating, filiform, flaccid, yellowish green, often with a reddish tinge, to 60 cm long. Lower bract leaf-like, terete, 3–5 cm long, shorter than inflorescence, erect; other bracts scarious, narrowly ovate; capitulum bracts castaneous, ovate to lanceolate, 1.5–3 mm long. Inflorescence racemes of 2–9 heads, 2–10 cm tall, with erect branches; heads obconic or rarely semiglobose, 2–5 (–12)-flowered, 4–13 mm in diam. Tepals unequal to ±equal, linear to narrowly lanceolate, light brown or greenish to reddish brown, later stramineous, prominently (1–) 3-veined; outer tepals ±acuminate-subulate, (2.1–) 2.8–4.9 mm long; inner tepals acute to mucronate, (2.1–) 2.8–5.5 mm long. Stamens 3 or 6, not exserted; anthers 0.5–0.8 mm long; filaments 0.8–1.7 mm long; style 0.1–0.2 mm long; stigmas 0.4–1 mm long. Capsules unilocular, narrowly ovoid to oblong-prismatic, sharply trigonous, often with concave valves, brown to dark brown, acute to acuminate below the rostrum, (3.2–) 3.5–6.1 mm long, c. 1.5–1.9 mm wide, usually exceeding (rarely equalling) perianth; rostrum c. 0.2–0.5 mm long. Seeds ellipsoid, apiculate, (0.5–) 0.6–0.7 × 0.2–0.3 mm distinctly reticulate; appendages absent. 2n = c. 112, c. 60, fide R.L.Taylor & G.A.Mulligan, Fl. Queen Charlotte Is. 2: 44 (1968). Fig. 98.