T: Uruguay, Entre Rios, prope Concepción, P.G.Lorentz 1126; holo: GOET; iso: BAF, CORD, photo AAU.
Perennials, 20–60 cm tall, caespitose; rhizome 1–3 mm in diam., densely branched or creeping with short internodes. Stems erect, rigid, 1–2.5 mm in diam., with 10–25 longitudinal ridges, ±bulbous at base, with the thickening covered with brown to castaneous scales; pith of rounded parenchymatous cells. Cataphylls 0–2 per stem, to 7 cm long; blade rudimentary, to 5 mm long; upper cataphylls with blades, 1–2 per stem, 10–25 cm long, usually to half as long as stem; sheaths 3–11 cm long, with scarious margins and auricles 0.5–1.0 mm long; blades filiform, 0.7–2.0 mm wide; leaf round or elliptic in T.S., ±striate, with adaxial enlarged (bulliform) cells absent. Lower bract 1.5–4.5 cm long, ±shorter than or equalling inflorescence, with well developed sheath and short blade. Inflorescence ±terminal or ±pseudolateral, compound, 1.5–7 × 1.5–3 cm, 15–100-flowered, of several unilateral, clustered cymes. Bracteoles 1.5–2.0 mm long. Tepals unequal, lanceolate, acute, green, later bright castaneous; margins scarious; outer tepals 4–5 mm long, with central band thicker, extending to a mucro; inner tepals c. 3.5 mm long. Stamens 3, 1.5–2.5 mm long; anthers 0.8–1.5 mm long, longer than 1 mm filaments. Capsule ellipsoid, obtuse to truncate, trigonous to trilobed in T.S., ±trilocular, 3.5–4.0 × 1.5–2.0 mm, castaneous, glossy, thick-walled, ±shorter than perianth. Seeds ellipsoid, apiculate, 0.3–0.4 × 0.15–0.2 mm, rugose or ridged, brown; appendages absent.