Scientific Name

Bromus diandrus Roth (Synonyms: Bromus rigidus)

Common Name(s)

Ripgut brome

Tribe / Family Name

Bromeae

Flowering Period

May to July

Symbol

BRDI3

Description

Ripgut brome is an introduced cool-season annual bunchgrass that reproduces from seeds. Culms range from 20–90 cm in height. Its inflorescence is an open, nodding to drooping panicle that is 13–25 cm long with erect to ascending or spreading branches. Spikelets are 25–70 mm long, moderately laterally compressed, and 4- to 11-flowered. Glumes are smooth or scabrous, hyaline along the margins, and unequal (lower glumes 15–25 mm long, 1- to 3-nerved; upper glumes 20–35 mm long, 3-to 5-nerved). Lemmas are 20–35 mm long, linear-lanceolate, glabrous or scabrous, hyaline along the margins, bifid at the apices, and awned (awns 30–65 mm long, rough-textured, stout, and arising below the lemma apices). Sheaths are usually closed nearly to the top and softly pilose with spreading hairs. Auricles are absent. Ligules are 2–3 mm long, membranous, obtuse, lacerate or erose, and glabrous. Blades are 10–20 cm long, 3–8 mm wide, flat, occasionally involute, erect to spreading, and hairy on both surfaces.

General Info

Ripgut brome can normally be found in overgrazed rangelands, post-fire settings, and disturbed sites, such as waste areas, fields, and roadsides.

Similar Species

Ripgut brome can look similar to other brome grasses, such as cheatgrass (Bromus tectorum) and Japanese brome (Bromus japonicus). Like ripgut brome, both species have seed heads that are nodding to drooping. Also, ripgut brome has seed heads that are much larger than cheatgrass and Japanese brome. Another similar characteristic of both ripgut brome and cheatgrass are the awns, which are long and straight. However, Japanese brome awns are bent and twisted, especially at maturity.