Plants annual; often tufted. Culms 30-60 cm, slender. Sheaths pilose-pubescent to nearly glabrous; blades 7-28 cm long, 2-9 mm wide, pilose or glabrous. Panicles 10-20 cm long, 3-9 cm wide, erect, dense; branches appressed to spreading, sometimes flexuous. Spikelets 15-20 mm, elliptic to lanceolate, more or less terete, with 3-9 florets. Glumes glabrous, acuminate; lower glumes 8-10 mm, 1-veined; upper glumes 12-16 mm, 3(5)-veined; lemmas 11-14 mm, lanceolate to linear-lanceolate, sparsely pubescent, 5-veined, rounded over the midvein, apices acuminate, bifid, teeth 2-3 mm, usually aristate, sometimes acuminate; awns 13-20 mm, geniculate, strongly to moderately twisted in the basal portion, arising 1.5 mm or more below the lemma apices; anthers 2-2.5 mm. 2n = unknown.

Bromus berteroanus is from Chile, and is now established in dry areas of western North America, including Montana, California, Nevada, Arizona, southwestern Utah, and Baja California, Mexico.

FNA 2007, Gould 1980

Common Name: Chilean chess Duration: Annual Nativity: Non-Native Lifeform: Graminoid General: Introduced, tufted annual 30-60 cm tall, slender. Vegetative: Sheaths pilose-pubescent to nearly glabrous, blades 7-28 cm long, 2-9 mm wide, pilose or glabrous. Inflorescence: Panicles 10-20 cm long, 3-9 cm wide, erect, dense; branches appressed to spreading, sometimes flexuous; spikelets 15-20 mm, elliptic to lanceolate, terete, with 3-9 florets; glabrous, acuminate glumes; lower glumes 8-10 mm, 1-veined, upper glumes 12-16 mm, 3-5 veined; lemmas 11-14 mm, lanceolate to linear-lanceolate, sparsely pubescent, 5-veined, rounded over midvein, acuminate apices, bifid, teeth 2-3 mm, awns 13-20 mm, geniculate, strongly to moderately twisted in basal portion, arising 1.5 mm or more below the lemma apices. Ecology: Found in dry areas, slopes from sea level to 3,000 ft (914 m); flowers February-June. Distribution: Originally from Chile, established in dry parts of North America, generally across the interior desert west and south into northern Mexico and Baja California. Notes: Found at a variety of elevations in Arizona. Difficult to ascertain its precise elevation range due to the spotty nature of its prior sampling. Ethnobotany: Unknown Etymology: Bromus is from Greek bromo, for stinking, while berteroanus is named for Carlo Giuseppe Bertero (1789-1831), an Italian physician. Synonyms: Bromus berterianus, B. trinii, B. trinii var. excelsus, Trisetobromus hirtus Editor: SBuckley, 2010