HABIT Perennial. Rhizomes short; pachymorph. Culms erect; reed-like; 180-230 cm long. Culm-internodes unequal, the upper longer; terete. Lateral branches lacking. Leaves with blades commonly suppressed, transferring photosynthetic function to sheath and culm. Ligule absent. INFLORESCENCE Synflorescence bractiferous; paniculate; with glumaceous subtending bracts; without axillary buds at base of spikelet. Fertile spikelets sessile. FERTILE SPIKELETS Spikelets comprising 1-3 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 7-12 mm long; breaking up at maturity; disarticulating below each fertile floret. GLUMES Glumes several; persistent; shorter than spikelet. Lower glume ovate; 0.7-0.8 length of upper glume; scarious; without keels; 3 -veined. Lower glume apex acute. Upper glume ovate; 0.6-0.8 length of adjacent fertile lemma; scarious; without keels; 3 -veined. Upper glume apex acute. FLORETS Fertile lemma ovate; scarious; without keel; 7 -veined. Lemma apex acute. Palea 1 length of lemma; scarious; 2 -veined. Palea keels ciliolate. Apical sterile florets 1 in number; barren; lanceolate. FLOWER Lodicules 3; membranous; acute. Anthers 3. Stigmas 2. DISTRIBUTION South America.