Bromus madritensis ssp. rubens

It is a winter annual grass, growing solitary or tufted, with erect or ascending culms growing 20–70 cm (7.9–27.6 in) high. The leaf sheaths are downy or slightly hairy. Its flat leaf blades are either glabrous or slightly hairy. The erect and ellipsoid panicles are 3–12 cm (1.2–4.7 in) long and 2–6 cm (0.79–2.36 in) wide, with short branches that ascend and slightly spread. The branches never droop and bear one or two spikelets each. The spikelets are 4–6 cm (1.6–2.4 in) long, longer than the panicle branches, and bear seven to eleven florets. The spikelets vary in color from green to distinctly purplish-red. The grass emerges in early winter and remains dormant until spring when heavy rainfall and higher temperatures stimulate growth. Plants flower from this period typically until May when water stress inhibits the grass. Young plants are green, but foliage and inflorescences become purplish at maturity, fading to light tan during the months following senescence. Areas of foxtail chess infestation can be recognized at a distance by their purplish color.