Scientific Name
Bromus hordeaceus L. (Synonyms: Bromus mollis)
Common Name(s)
Soft brome, soft chess
Tribe / Family Name
Bromeae
Flowering Period
May to July
Symbol
BRHO2
Description
Soft brome is an introduced cool-season annual (sometimes biennial) bunchgrass that reproduces from seeds. Culms range from 2–70 cm in height. Its inflorescence is an erect, narrow panicle or occasionally a raceme 1–13 cm long with crowded spikelets. Spikelets are usually 14–20 mm long, lanceolate, soft-pubescent to glabrous, cylindrical and moderately laterally compressed, 5- to 10-flowered, and awned (awns are 6–8 mm long, straight to recurved at maturity, and originating below the lemma tips). Ligules are up to 1.5 mm long, membranous, obtuse to truncate, erose, glabrous or usually hairy.
General Info
Soft brome is normally found in sagebrush, meadows, pastures, foothills, low valleys, and disturbed areas including transportation corridors, irrigation ditches, cultivated fields, sandy beaches, and waste land.
Similar Species
Soft brome may look similar to Japanese brome (Bromus arvensis). However, the inflorescence of soft brome is more erect and does not appear to be nodding or drooping over like Japanese brome. Also, soft brome has small, hairy spikelets with straight awns, but become recurved at maturity, while Japanese brome has large, smooth or scabrous spikelets with awns that become twisted and geniculate at maturity. Other similar species include cheatgrass (Bromus tectorum) and rattlesnake brome (Bromus briziformis), which also have inflorescences that appear to be nodding or drooping over. However, cheatgrass has long, straight awns, and rattlesnake brome is awnless or short awned.
Picture of growth habit.
Inflorescence is an erect, narrow panicle.
Close-up picture of spikelet.
Close-up picture of membranous ligule.
Illustration of soft brome. USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. <i>An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols</i>. Charles Scribner's Sons, New York. Vol. 1: 278.
Distribution map of soft brome. USDA PLANTS Database, 2022.