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Montana Field Guides

Field Brome - Bromus arvensis

Not Documented

Global Rank: GNR
State Rank: SNA
(see State Rank Reason below)
C-value: 1

Agency Status


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State Rank Reason (see State Rank above)
Bromus arvensis is not documented in Montana (; Lesica et al. 2012; Cronquist et al. 1977; Hitchcock et al. 1969). This grass is reported for Montana based on the species' distribution map in the Flora of North America (FNA; Pavlick and Anderton in FNA 2007). Although the FNA (2007) map indicates its presence in vicinity of the Gallatin, Park, and/or Broadwater county region of Montana, supporting specimens or literature have not found (MTNHP Status Review in 2022); further the Bromus treatment (FNA 2007) was submitted by Leon Pavlick who died before it could be reviewed and edited. The NRCS PLANTS [] database is basing the Montana records of Bromus arvensis on their inclusion of Bromus japonicus as a synonym to Bromus arvensis; however, the website provides no literature reference. Further Bromus japonicus is an accepted name and a distinct species (;; Lesica et al. 2012; Giblin et al. [eds.] 2018; Cronquist et al. 1977; Hitchcock et al. 1969). A conservation status rank is not applicable (SNA) because this grass is not known to occur in Montana.

NOTE: Potential specimens should be sent to a State herbaria (University of Montana, Montana State University, or Montana State University-Billings) for verification. Herbarium specimens allow identifications to be confirmed, provide a central location for educating and information sharing, are a source for genetic, morphological, and ecological research, and are the basis on which Montana's floras are written.
General Description
Adapted from Pavlick and Anderton in Flora of North America 2007:

PLANTS: Erect annuals 80-110 cm tall. Lower sheaths with dense, soft, appressed hairs.

LEAVES: Blades 10-20 cm long, 2-6 mm wide, coarsely pilose on both surfaces. Ligules 1-1.5 mm long, hairy, obtuse, erose.

INFLORESCENCE: Panicles 11-30 cm long, 4-20 cm wide, open, erect or nodding; branches usually longer than the spikelets, ascending to widely spreading. Spikelets 10-25 mm long, terete to moderately compressed, often purple-tinged; florets 4-10. Glumes glabrous; lower glumes 4-6 mm long, 3-veined; upper glumes 5-8 mm long, 5-veined; lemmas 7-9 mm long, obscurely 7-veined, rounded over the midvein, glabrous, apices acute, bifid, teeth less than 1 mm long; awns 6-11 mm, straight; anthers 2.5-5 mm long. Fruit is a caryopsis: shorter than the paleas, weakly to strongly inrolled.

Diagnostic Characteristics
Field Brome - Bromus arvensis, exotic, undesirable, and NOT documented in Montana
*Spikelets purplish-tinged and
*Anthers 2.5-5 mm long and
*Lower leaf sheaths with soft appressed hairs.

Japanese Brome - Bromus japonicus, exotic and undesirable
*Spikelets not purple-tinged and with close together lemmas that cover the rachilla and
*Anthers 1-1.5 mm long and
*Lower leaf sheaths are usually densely pilose.

Rye Brome - Bromus secalinus, exotic and undesirable
*Spikelets twisted, not purplish-tinged, and with distinct lemmas separated enough to expose the rachilla and
*Anthers 1-2 mm long and
*Lower leaf sheaths glabrous or loosely pubescent and glabrate.

Range Comments
Scattered locations in Canada and the United States (Pavlick and Anderton in FNA 2007). Seldom collected in the Pacific Northwest (Giblin et al. [eds.] 2018).

Native to southern and south-central Europe (Pavlick and Anderton in FNA 2007).

Along roadsides, fields, and waste areas (Pavlick and Anderton in FNA 2007).


  • Literature Cited AboveLegend:   View Online Publication
    • Cronquist, A., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1977. Intermountain flora: Vascular Plants of the Intermountain West, U.S.A. Volume 6: The Monocotyledons. New York, NY: Columbia University Press. 584 pp.
    • Flora of North America Editorial Committee. 2007. Flora of North America North of Mexico. Vol. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford Univ. Press, New York. xxviii + 911 pp.
    • Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1969. Vascular plants of the Pacific Northwest. Part 1: Vascular Cryptogams, Gymnosperms, and Monocotyledons. University of Washington Press, Seattle. Sixth printing 1994, 914 pp.
    • Hitchcock, C.L. and A. Cronquist. 2018. Flora of the Pacific Northwest: An Illustrated Manual. Second Edition. Giblin, D.E., B.S. Legler, P.F. Zika, and R.G. Olmstead (eds). Seattle, WA: University of Washington Press in Association with Burke Museum of Natural History and Culture. 882 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
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Citation for data on this website:
Field Brome — Bromus arvensis.  Montana Field Guide.  .  Retrieved on , from