Roland von Bothmer, Claus Baden, Niels H. Jacobsen (2007) FNA 24:241-252
Plants perennial; loosely to densely cespitose. Culms to 90 cm, erect to geniculate, not bulbous; nodes glabrous. Sheaths glabrous or densely pubescent; auricles absent; blades to 19 cm long, to 8 mm wide, glabrous or with hairs on both surfaces, hairs sometimes of mixed lengths. Spikes 3-8.5 cm, green to somewhat purple. Glumes 7-19 mm, ascending to slightly divergent at maturity. Central spikelets: glumes 9-19 mm long, about 0.2 mm wide, setaceous throughout, rarely flattened near the base; lemmas 5.5-10 mm, usually glabrous, rarely pubescent, awned, awns 3.5-14 mm; anthers 0.8-4 mm. Lateral spikelets staminate; glumes 7-19 mm, setaceous; lower glumes sometimes flattened near the base; lemmas rudimentary to well developed, awns to 7.5 mm, rarely absent; anthers 0.8-4 mm. 2n = 14, 28, 42.
Hordeum brachyantherum is native to the Kamchatka Peninsula and western North America, and has been introduced to a few locations in the eastern United States. There is also a small disjunct population in Newfoundland and Labrador that Baum (1978) identified as H. secalinum. Hordeum brachyantherum grows in salt marshes, pastures, woodlands, subarctic woodland meadows, and subalpine meadows.
Two subspecies are recognized here, but there is so much overlap in their morphological variation that unambiguous determination of many specimens is impossible in the absence of a chromosome count. They are sometimes treated as two species.
2n = 14, 28; haplomes I (sensu Blattner 2209)
Bothmer et al. (1995) reported that Hordeum brachyantherum is usually diploid or tetraploid but they included one hexaploid population in the species as Hordeum brachyantherum subsp. californicum which is treated on this site as Hordeum californicum, following Brassac and Blattner (2015).