1.  Lateral awns < 12 mm long, < half as long and half as thick as central awn (this to 30  mm long)…

1.  Lateral awns 10 or more mm, > half the length of the central awn…2

2.  Inflorescence a dense foxtail > 15 mm wide (excluding awns) wide…

2.  Inflorescence otherwise…3

3.  Wetland grass with well developed scaly rhizome; upper glume with awn > (3)-7 mm… (basal sheath shredding) (central awn 15-30 mm long, horizontal to reflexed; lateral awn 13-20 mm)

3.  Wetland or dry habitat grass without strongly developed rhizome; upper glume with no awn or with awn < 3 mm long…4

4.  Leaf blades predominantly flat toward the base of the plant…5

4.  Leaf blades involute…6

5.  Leaf blades curled; lower glume < 9 mm long; ligule < 0.1 mm long; central awn 8-25 mm…

5.  Leaf blades usually not curled; lower glume > 9 mm long; ligule 0.2 mm long; central awn 15-40 mm long…

6.   Awns contorted (also true in A. purpurascens var. tenuispica with flat leaves and   equal glumes); glumes unequal; callus usually > 1 mm long; leaf collars glabrous; awns nearly equal…

6.   Awns not contorted; glumes nearly equal; callus usually 0.4-0.6 mm; leaf collars pubescent; lateral awns a little shorter than central awn…