Hordeum

1. Body of larger lemmas ca. 8–11 mm long; leaves glabrous, with prominent auricles at base of blade; awns of lemmas much stouter than those of glumes; rachis of spike not disintegrating.

H. vulgare

1. Body of larger lemmas ca. 3.5–6 mm long; leaves (at least lower sheaths) ± pubescent, without auricles; awns of lemmas as slender as those of glumes; rachis of spike readily disintegrating as it matures.

2. Awns much longer than 2 cm; glumes all bristle-like (reduced to awns).

H. jubatum

2. Awns less than 2 cm long; glumes in part broadened (± lanceolate).

H. pusillum

All species found in Hordeum

Hordeum jubatumSQUIRREL-TAIL GRASS 
Hordeum pusillumLITTLE BARLEY 
Hordeum vulgareBARLEY 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. September 25, 2017. http://michiganflora.net/genus.aspx?id=Hordeum.