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- True grasses
- Bromus commutatus
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
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
Found this plant? Take a photo and post a sighting.
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
-
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).