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Bromus marginatus — large mountain brome

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Facts

Large mountain brome is native to western North America, and introduced in New York and New England, where it inhabits fields, roadsides and disturbed soils. This species is sometimes used in erosion control and revegetation projects, which may account for its presence in our region.

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
Leaf blade width
1–12 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
20–40 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
4–7 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
Leaf ligule length
2–3.5 mm
Anther length
1–6 mm
Show all characteristics
  • Flowers

    Anther length
    1–6 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
    4–9
    Floret types within spikelet
    all the florets within a spikelet are similar
    Glume awn length
    0 mm
    Glume keel
    • the glume keels are rough or hairy
    • the glume keels are smooth and hairless
    Glume relative length
    neither glume is quite as long as all of the florets
    Glume shape
    the glume is V-shaped in cross-section
    Glume veins
    • 3
    • 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 length
    3–5 cm
    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
    1–4
    Inflorescence crowding
    • the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
    • the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    50–300 mm
    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
    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
    4–7 mm
    Lemma awn number
    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 V-shaped 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
    the keel of the lemma is rough, or has fine hairs
    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 long narrow 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
    7–9 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
    20–40 mm
    Spikelet number per node
    Up to 0
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet shape
    • the spikelets are elliptic (widest in the middle, tapering to the ends) in profile
    • the spikelets are lanceolate (lance-shaped, widest below the middle and tapering narrowly to the ends) in profile
    Spikelet width
    5–8 mm
    Spikelets per panicle branch
    1–2
    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
    9–11 mm
    Upper glume relative length
    the upper glume is more than one half as long as the lowest lemma
    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

    Lifespan
    the plant lives more than two years
  • Leaves

    Leaf auricles
    • the leaves do not have auricles
    • the leaves have auricles
    Leaf blade cross-section
    • the leaf blade is clearly folded or rolled inwards
    • 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
    8–25 cm
    Leaf blade width
    1–12 mm
    Leaf ligule length
    2–3.5 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
    Leaf sheath hairs
    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
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • Stem, shoot, branch

    Hairs at nodes
    the stem nodes have hairs that stand out at a shallow angle, or they curve downwards
    Plant height
    45–120 cm
    Stem hairs
    the stem has hairs on it
    Stem orientation
    the stems are upright
    Stem spacing
    the stems grow close together in compact clusters or tufts

Wetland status

Not classified

In New England

Distribution

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

Conservation status

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

Massachusetts
unranked (S-rank: SNR)

From Flora Novae Angliae dichotomous key

12.  Bromus marginatus Nees ex Steud. E

large mountain brome. Bromus breviaristatus Buckl.; B. carinatus Hook. var. linearis Shear; B. carinatus Hook. var. marginatus (Nees ex Steud.) Barkworth & Anderton; Ceratochloa marginata (Nees ex Steud.) W.A. Weber • CT, MA, ME, NH. Fields, roadsides, disturbed soil.

Native to North America?

Yes

Sometimes confused with

Bromus kalmii

Synonyms

  • Bromus breviaristatus Buckl.
  • Bromus carinatus Hook. var. linearis Shear
  • Bromus carinatus Hook. var. marginatus (Nees ex Steud.) Barkworth & Anderton
  • Ceratochloa marginata (Nees ex Steud.) W.A. Weber

Family

Poaceae

Genus

Bromus