T: Argentina, Neuquén, Quetrihué, lago Nahuel Huapí, 11 Feb 1947, J.Diem 1001; holo: SI; iso: LIL.
Perennials, c. 17–35 cm tall. Rhizome creeping, horizontal, ±stoloniform, c. 1.5 mm in diam., with internodes often elongated, rooting at nodes. Cataphylls scaly. Stem erect to ascending, c. 1.0–1.4 mm in diam., with intra- and extravaginal shoots. Cauline leaves several, ±equalling stem or longer; sheaths lax, 2.5–5.5 cm long; auricles c. 2–4 mm long, usually unequally inserted (0.3–10 mm from one another); blade 13–18 cm long, 0.8–2 mm wide; unitubular, canaliculate in proximal part, perfectly septate (sometimes imperfectly so at base of blade); septa visible externally. Inflorescence anthelate, compound, to c. 10 cm long, 5–20 small conical or semiglobose 3–5-flowered heads 5–8 mm in diam. Tepals lanceolate, 4.0–4.5 mm long, acute, subequal; outer tepals slightly longer, pale brown, often suffused reddish; margins broad, membranous. Stamens 6, 3.0–3.5 mm long; anthers c. 1.2–1.6 mm long, slightly shorter than c. 1.5–2.0 mm filaments; style c. 1 mm long; stigmas exserted, c. 3 mm long. Capsule ±ellipsoid, 5 mm long, mucronulate, trigonous, usually slightly longer than perianth, pale brown. Seeds obliquely ovoid, c. 0.5 mm long, apiculate, reticulate; appendages absent.