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Native Plant Trust: Go Botany Discover thousands of New England plants

Bromus commutatus — meadow brome

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Facts

Meadow brome is native to Europe and western Asia and widely introduced in North America, where it is considered a noxious weed in some states. It is found in all New England states.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf blade width
2–4 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
14–30 mm
Glume relative length
neither glume is quite as long as all of the florets
Awn on glume
the glume has no awn
One or more florets
there is more than one floret per spikelet
Lemma awn length
3–10 mm
Leaf sheath hair type
  • there are hairs on the surface of the leaf sheath, but the hairs do not have blisters at their bases
  • there are no hairs on the surface of the leaf sheath
Leaf ligule length
1–2.5 mm
Anther length
0.7–1.7 mm
Show all characteristics
  • Flowers

    Anther length
    0.7–1.7 mm
    Anther number
    2–3
    Awn on glume
    the glume has no awn
    Bristles below spikelets
    no
    Floret lower bract texture
    the lemma is thin and flexible
    Floret number
    4–11
    Floret types within spikelet
    all the florets within a spikelet are similar
    Glume awn length
    0 mm
    Glume relative length
    neither glume is quite as long as all of the florets
    Glume veins
    • 5
    • 7 or more
    Glumes per spikelet
    2
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    • the inflorescence axis is arched or curved outward
    • the inflorescence axis is straight
    Inflorescence branch roughness
    the inflorescence branches are somewhat to very rough
    Inflorescence branches
    the flowers are attached to branches rather than to the main axis of the inflorescence
    Inflorescence branches coming off the lowest stem node
    2–6
    Inflorescence crowding
    the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    90–180 mm
    Inflorescence length to width ratio
    3
    Inflorescence type (general)
    the spikelets are borne on stalks or on branches
    Inflorescence type (specific)
    the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes
    Inflorescence width
    30–60 mm
    Inforescence position
    the spikelets are mainly carried at the end of the stem
    Lemma awn base
    the awn is attached right at the tip of the lemma
    Lemma awn coiled
    the lemma awn is straight or twisted, but not coiled one half turn
    Lemma awn length
    3–10 mm
    Lemma awn number
    • the lemma has no awn
    • the lemma has one awn on it
    Lemma awn orientation
    • the awn of the lemma is straight
    • the awn of the lemma on dried or older plants is curved or bent outwards
    Lemma base hair length
    0 mm
    Lemma base hairs
    the lemma is hairless or feels just a tiny bit rough at the base
    Lemma cross-section
    the lemma is flat or rounded if you cut across the midpoint
    Lemma hairs
    • the lemma has fine hairs between the veins
    • the lemma is hairless between the veins
    Lemma keel hairs
    NA
    Lemma marginal vein hairs
    • the marginal vein of the lemma has fine hairs on it
    • the marginal vein of the lemma is hairless
    Lemma surface
    the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)
    Lemma tip
    the lemma tip is split into two or more points
    Lemma tip shape
    • the lemma tip tapers to a broad point (it may or may not also have an awn or teeth at the tip)
    • the lemma tip tapers to a narrow point (it may or may not also have an awn or teeth at the tip)
    Lemma vein number
    7 or more
    Lemma vein orientation
    the veins on the lemma come together near the tip
    Lower glume length
    5–7 mm
    One or more florets
    there is more than one floret per spikelet
    Palea relative length
    palea is one half to fully as long as lemma
    Reproductive system
    all the flowers on the plant have both carpels and stamens (synoecious)
    Spikelet axis tip
    there is an extension of the spikelet axis beyond the tip of the spikelet
    Spikelet disintegration
    the spikelet breaks off above the glumes, so that after the florets fall off, the glumes remain
    Spikelet length
    14–30 mm
    Spikelet number per node
    Up to 0
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet shape
    • the spikelets are lanceolate (lance-shaped, widest below the middle and tapering narrowly to the ends) in profile
    • the spikelets are oblong (rectangular, but with rounded ends) in profile
    Spikelet width
    10–15 mm
    Spikelets per panicle branch
    1–3
    Spikelets spiny
    the spikelets do not appear spiny
    Tip of glume
    the tip of the glume is not divided (though it may have an awn on it)
    Upper glume length
    6–9 mm
    Upper glume shape
    the upper glume is widest at or below the middle
  • Fruits or seeds

    Groove on seed
    the caryopsis has a groove running most of its length
  • Growth form

    Horizontal rooting stem
    no
    Lifespan
    the plant lives only a single year or less
    Rhizomes
    no
    Roots
    there are only slender roots on the plant
  • Leaves

    Leaf blade cross-section
    the leaf blade is more or less flat in cross-section, or slightly folded or rolled inwards
    Leaf blade hairs
    • the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel
    • the leaf blade is hairy
    Leaf blade length
    9–18 cm
    Leaf blade texture
    the leaf blade is smooth, or it may have soft hairs
    Leaf blade width
    2–4 mm
    Leaf ligule length
    1–2.5 mm
    Leaf ligule type
    the leaf ligule is in the form of a membrane
    Leaf margin glands
    there are no glands along the edges of the leaf blade
    Leaf sheath closed around stem
    the margins of the leaf sheath are fused together and form a closed tube except (possibly) at the very top
    Leaf sheath hair type
    • there are hairs on the surface of the leaf sheath, but the hairs do not have blisters at their bases
    • there are no hairs on the surface of the leaf sheath
    Leaf sheath hairs
    • there are hairs on the surface of the leaf sheath
    • there are no hairs on the surface of the leaf sheath
    Orientation of topmost leaf
    the flag leaf is held upright, or at less than a 45 degree angle out from the stem
  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • Stem, shoot, branch

    Hairs at nodes
    • the stem nodes are hairless or they have very sparse hairs
    • the stem nodes have hairs that stand out at a shallow angle, or they curve downwards
    Plant height
    40–120 cm
    Stem hairs
    the stem is nearly to completely hairless
    Stem orientation
    the stems are upright

Wetland status

Not classified

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
present
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
not applicable (S-rank: SNA)

From Flora Novae Angliae dichotomous key

4.  Bromus commutatus Schrad. E

meadow brome. CT, MA, ME, NH, RI, VT. Fields, roadsides, disturbed soil.

Native to North America?

No

Sometimes confused with

Bromus japonicus:
branches of panicle using arching or dropping, apical lobes of lemma 1.5-3 mm long, and lemma awns broad and flattened at base, divergent at maturity (vs. B. commutatus, with branches of panicle stiffly erect to spreading, apical lobes of lemma up to 1.5 mm long, and lemma awns terete or scarcely flattened at the base, not or only slightly divergent at maturity).
Bromus hordeaceus:
lemmas 3-5 mm wide, with prominently raised veins, and panicles mostly 3-10 cm tall (vs. B. commutatus, with lemmas 1.7-2.6 mm wide, veined, but the veins not prominently raised, and panicles mostly 7-16 cm tall).

Family

Poaceae

Genus

Bromus