Plants densely or loosely cespitose, without rhizomes. Culms (5)8–35(55) cm, erect, usually smooth and glabrous, sometimes sparsely scabrous or puberulent near the inflor-escence. Sheaths closed for about 1/2 their length, smooth or scabrous, persistent or slowly shredding into fibers; collarsglabrous; ligules 0.1–0.4 mm; blades (0.3)0.5–1(1.2) mm in diameter, con-duplicate, abaxial surfaces smooth or sparsely scabrous, adaxial surfaces scabrous, veins (3)5–7, ribs 3–5; abaxial sclerenchyma in 3–7(9) narrow strands, usually less than twice as wide as high; adaxial sclerenchymaabsent; flag leaf sheaths not inflated, more or less tightly enclosing the culms; flag leaf blades (0.3)1–2.5(3) cm. Inflorescences 1.5–4(5.5) cm, contracted, usually panicles, very rarely racemes, with 1–2 branches per node; branches usually erect, sometimes spreading at anthesis, lower branches with 2+ spikelets. Spikelets 3.5–7(8.5) mm, with 2–4(6) florets. Glumes exceeded by the upper florets, ovate-lanceolate, usually glabrous and smooth, sometimes scabrous distally; lower glumes (1.2)1.8–3(3.5) mm; upper glumes (2.4)2.6–4(4.6) mm; lemmas 2.5–4.5(6) mm, ovate-lanceolate to lanceolate, scabrous towards the apices, awns (0.8)1–3(3.5) mm, terminal; paleas about as long as the lemmas, intercostal region scabrous or puberulent distally; anthers (0.5)0.7–1.1(1.3) mm; ovary apices glabrous. 2n = 28, 42, 44.
Festuca brachyphylla is a variable, circumpolar, arctic, alpine, and boreal species of open, rocky places. It is palatable to livestock, and is important in some areas as forage for wildlife. The spikelets are usually tinged red to purple by anthocyanin pigments; plants which lack anthocyanins in the spikelets have been named F. brachyphylla f. flavida Polunin. Festuca brachyphylla has frequently been included in F. ovina, and it is closely related to F. saximontana, F. hyberborea, F. edlundiae, F. groenlandica, and F. minutiflora. It may hybridize with F. baffinensis and/or other species to form F. viviparoidea.