Plants densely cespitose, without rhizomes. Culms 35-80 (100) cm, usually densely scabrous or densely pubescent below the inflorescences. Sheaths closed for less than 1/2 their length, glabrous, smooth or scabrous, persistent; collars glabrous, smooth or scabrous; ligules 0.5-1.5(2) mm; blades 0.3-0.8 mm in diameter, conduplicate, abaxial surfaces scabrous or puberulent, adaxial surfaces scabrous to pubescent, veins 5-7, ribs (1)3-5(7), distinct; abaxial sclerenchyma in 5-7 broad strands, rarely forming a complete band, forming pillars with some veins; adaxial sclerenchyma not developed. Inflorescences (4)6-15(20) cm, loosely contracted or open, with 1-2 branches per node; branches erect or spreading, lower branches with 2+ spikelets. Spikelets (6)8-16 mm, with (3)4-6(8) florets. Glumes exceeded by the upper florets, lanceolate, glabrous, smooth or scabrous distally; lower glumes (3)3.3-5.5 mm; upper glumes 4.5-6.6(7) mm; lemmas 5.5-9 mm, glabrous, smooth or scabrous towards the apices, unawned or awned, awns 0.4-2(3) mm; paleas slightly shorter than the lemmas, intercostal region scabrous or puberulent distally; anthers (2)3-4(4.2) mm; ovary apices densely pubescent. 2n = 42.
Colo., N.Mex., Tex., Utah, Ariz., Nev.
Festuca arizonica grows in dry meadows and openings of montane forests, in gravelly, rocky soil, at 2100-3400 m. Its range extends from southern Nevada and southern Utah east to Colorado and south to Arizona, western Texas, and northern Mexico. It is abundant and valuable forage in some parts of its range. It is often found with F. calligera (see previous).
Festuca arizonica differs from F. idahoensis (see next), with which it is sometimes confused, in its prominently ribbed blades and pubescent ovary apices. It has frequently been included in F. ovina (p. 422).