Bromus hordeaceus L.

Family: Poaceae, Tribe: Bromeae

Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)

Bromus confertus Boreau, B. mollis L., B. molliformis Lloyd

Pertinent Common Names (particularly those used in California; go to GRIN for other common names)

soft brome

Primary Disseminule Type


Description (diagnostics are in brown)

Spikelets solitary, pedicelled, consisting of 6–12 fertile florets with similar-looking though diminished sterile florets at apex, ovate to lanceolate, slightly laterally compressed to terete, 11–23 mm long x 3.5–6(8) mm wide, disarticulating below each fertile floret at maturity.

Glumes persistent, similar, shorter than spikelet, parallel to lemmas, chartaceous, without keel. Lower glume oblong or ovate, 5–8 mm long, 0.8–0.9 length of upper glume, 3–5(7)-veined, apex acute. Upper glume elliptic, 5–9 mm long, 0.7–0.8 length of adjacent fertile lemma, 5–7(9)-veined, apex acute.

Fertile florets: rachilla persistent, minutely pubescent, callus short, blunt, glabrous.

Lemma elliptic to obovate, (6.5)8–11 mm long x 2.5–5 mm wide, chartaceous to membranous, much thinner on margins, with rounded back (no keel) to slightly keeled, 7–9-veined, midvein and lateral veins ribbed, surface hirsute, apex acute, bifid, teeth 0.5–1.5 mm long, awn subapical, 3–10 mm long, slender, straight or sometimes curved outward, scabrous.

Palea 0.8 length of lemma, hyaline, keels ciliolate.

Caryopsis fusiform to oblanceolate, edges weakly inrolled, 4.5–7 mm long x 1.5–2 mm wide, brown, apex fleshy and hairy, hilum linear, same length as caryopsis.

Similar Species

Similar Species Comparison Chart

Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)