Scientific Name
Bromus inermis Leyss.
Common Name(s)
Smooth brome
Tribe / Family Name
Bromeae
Flowering Period
June to August
Symbol
BRIN2
Description
Smooth brome is an introduced cool-season perennial rhizomatous sod-forming grass; reproduction occurs by seeds, tillers, and rhizomes. Culms range from 50–130 cm in height. Its inflorescence is a narrow to open panicle 10–20 cm long with ascending and whorled lower branches. Spikelets are 20–40 mm long, terete, usually 5 to 10 flowered, and unawned or awned (awns up to 3 mm long and arising just below the lemma tips). Auricles are sometimes present. Ligules are up to 3 mm long, membranous, obtuse to truncate, erose to ciliolate, and glabrous. Blades with a conspicuous “W” or “M” crimped into them.
General Info
Smooth brome can be found in moist to dry sites such as meadows and pastures, riparian zones, forests, roadsides and waste places.
Similar Species
Smooth brome can look similar to mountain brome (Bromus marginatus). The growth habit of smooth brome is a rhizomatous sod-forming grass, and mountain brome is a bunchgrass. Also, smooth brome has spikelets that are terete and either awned (up to 3 mm long) or unawned, and mountain brome has spikelets that are strongly compressed and awned up to 8 mm long. Additionally, the leaves of smooth brome has a conspicuous “W” or “M” crimped into the widest part of the leaf, and mountain brome does not.
Picture of growth habit.
Close-up picture of narrow to open-panicle inflorescence.
Close-up picture of spikelet. Note the spikelet does not have awns.
Close-up picture of spikelet. Note the spikelet has awns.
Close-up picture of membranous ligule.
Illustration of smooth 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: 277.
Distribution map of smooth brome. USDA PLANTS Database, 2022.