HABIT Perennial. Culms erect; 38-63.25-100 cm long. Culm-nodes constricted (1), or swollen (1). Leaves differentiated into sheath and blade, or with blades commonly suppressed, transferring photosynthetic function to sheath and culm. Ligule absent. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades linear, or lanceolate. INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence. Inflorescence composed of racemes. Racemes paired; erect; unilateral. Rhachis angular. Sexes segregated; on unisexual branches; with male conjugate. Spikelets solitary. Fertile spikelets pedicelled. Male spikelets pedicelled. Pedicels cuneate. FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4.98-7.295-9 mm long; breaking up at maturity; disarticulating below each fertile floret. GLUMES Glumes persistent; shorter than spikelet (1), or exceeding apex of florets (1); thinner than fertile lemma. Lower glume lanceolate (1), or oblong (1); 0.75-0.925-1.1 length of upper glume; herbaceous; without keels; 3 -veined (1), or 5 -veined (1). Lower glume apex emarginate (1), or acuminate (1). Upper glume lanceolate (1), or oblong (1); 0.33-0.765-1.2 length of adjacent fertile lemma; herbaceous; without keels; 3 -veined. Upper glume lateral veins with cross-veins. Upper glume apex emarginate (1), or acute (1). FLORETS Fertile florets female. Fertile lemma lanceolate; coriaceous; without keel. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn flexuous. Palea coriaceous; 2 -veined. MALE Male spikelets distinct from female; lanceolate. Male spikelet glumes absent. Male spikelet lemma muticous. DISTRIBUTION South America.