Bromus secalinus is a species of bromegrass known as rye brome.<ref name=BSBI07>Template:Cite web</ref> The specific epithet secalinus is Latin, meaning "rye-like". The fruits are hard, rounded glumes that appear superficially similar to the rye grain, which gives the brome its common and scientific name. The grass has a diploid number of 28.
Bromus secalinus is an annual grass that grows Template:Convert high. The upper sheaths are smooth and strongly nerved, and the lower sheaths are glabrous or slightly pubescent. The leaf blades are Template:Convert long and Template:Convert wide, and are covered with short hairs. The panicles are Template:Convert long and Template:Convert wide with spreading or ascending branches. The spreading inflorescence nods when it becomes heavy with grain though prior to maturity the panicle is erect. The spikelets are on elongated pedicels, with each spikelet bearing five to fifteen flowers. The spikelets are glabrous or scabrous and become lax when mature. The ovoid spikelets measure Template:Convert long. The rachilla is obvious in youth and becomes obscured by the expanding florets with age. The lower glumes are three to five-veined and Template:Convert long, and the upper glumes are seven-veined and Template:Convert long. The lemmas become spreading when mature and are strongly inrolled. The lemmas have seven inconspicuous nerves and are Template:Convert long and Template:Convert wide. The awns are straight or curved and are Template:Convert long. The palea is as long or longer than the lemma and its tip slightly projects at maturity. The anthers are Template:Convert long. The caryopses are thick and strongly inrolled when mature.<ref name=Manual>Template:Cite book</ref><ref name=Flora>Template:Cite book</ref>
The grass flowers from June to September.
In youth the two brome grasses Bromus secalinus and Bromus arvensis are very similar, but are easily distinguishable in maturity. Bromus arvensis has fully pubescent leaves but Bromus secalinus lacks trichomes on the undersides of leaves.<ref name=GramBrit>Template:Cite book</ref>
Habitat and distribution
Bromus secalinus occurs in fields areas, road verges, and occasionally cornfields, in lightly stony soils.<ref name=GramBrit/>