Buchenau in H.G.A.Engler, Pflanzenr. , IV, 36: 202 (1906)
T: [Uruguay, Montevideo] Monte Video, M.Anderson; holo: G-DEL, photo PRA.
Perennials, c. 30–50 cm tall, loosely caespitose; rhizome horizontal, probably creeping; stem erect. Cataphylls developed, usually 1–2, brownish, lax; blade rudimentary. Cauline leaves 2–4, unitubular, 5–10 (–20) cm long, 1.5–2.0 mm in diam., perfectly septate; septa visible externally but not prominent in dry condition; sheaths 6–7 cm long, lax, with ±narrow distinct membranous margins; auricles obtuse, probably membranous, c. 1–1.5 mm long. Lower bract leaf-like, shorter than inflorescence. Inflorescence decompound, anthelate, of 8–16 usually ±globose to semiglobose heads; heads 5–20-flowered, 8–10 mm in diam., on straight erect to erecto-patent peduncles; flowers on pedicels to c. 1.5 mm long. Tepals ±equal; outer tepals ±broadly lanceolate, c. 3.0–3.5 mm long, subacute and mucronate, with central band castaneous-brown and suffused reddish and margins broad and membranous; inner tepals oblong to broadly oblong, sometimes ±slightly longer, obtuse and usually mucronate, with margins (particularly distally) very broad. Stamens 6, usually c. 3/4 as long as tepals; anthers c. 1.0–1.5 mm long, ±as long as filaments; style c. 1–2 mm long, exserted; stigmas long. Capsule unilocular, trigonous-ovoid with ±flat sides, c. 4–5 mm long including narrow 0.6–1.0 mm rostrum, subabruptly narrowing in rostrum, light castaneous, conspicuously exceeding perianth. Seeds ±ovoid, c. 0.6 mm long, pale brown, reticulate; appendages absent.