识别要点：Habit Perennial. Rhizomes elongated; scaly. Culms erect; 50-230 cm long; 1.5-4.5 mm diam. Leaf-sheaths 10-40 cm long; glabrous on surface, or pilose. Leaf-sheath auricles erect. Ligule an eciliate membrane; 2-5 mm long. Leaf-blades 10-50 cm long; 1-4 mm wide. Leaf-blade surface glabrous, or pubescent. Leaf-blade margins scabrous. Leaf-blade apex attenuate. Inflorescences Inflorescence a panicle with branches tipped by a raceme. Peduncle 20-60 cm long. Panicle open; oblong; dense; 10-35 cm long. Panicle axis villous. Racemes bearing a triad of spikelets, or few fertile spikelets; 1-3 fertile spikelets on each. Rhachis fragile at the nodes. Rhachis internodes filiform. Spikelets in pairs, or in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster, or 2 in the cluster. Pedicels filiform; 3-6 mm long; pubescent. Spikelets Companion sterile spikelets represented by barren pedicels. Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 5-8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse. Sterile Companion sterile spikelets represented by barren pedicels. Fertile Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 5-8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse. Glume Glumes dissimilar; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; light brown; without keels; 7-9 -veined. Lower glume surface pubescent. Lower glume apex truncate. Upper glume oblong; 1 length of spikelet; coriaceous; light brown; without keels; 5 -veined. Upper glume surface glabrous. Upper glume apex acute. Florets Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 4-6 mm long; hyaline; 2 -veined; ciliate on margins; dentate; 2 -fid. Fertile lemma oblong; 3-5.5 mm long; hyaline; without keel; 3 -veined. Lemma margins ciliolate. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10-22 mm long overall; with twisted column. Column of lemma awn hispidulous. Palea absent or minute. Flowers Lodicules 2; glabrous. Anthers 3; 3-5 mm long. Fruits Caryopsis 2.3 mm long.

分布：Australasia: Australia. North America: eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Brazil.