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Hordeum murinum — mouse barley

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Facts

Mouse barley is a non-native grass that is occasionally found in Connecticut, Massachusetts and Maine.

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
Leaf blade width
2–5 mm
Inflorescence branches
  • the flowers are attached to branches rather than to the main axis of the inflorescence
  • there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
Glume relative length
neither glume is quite as long as all of the florets
Awn on glume
the glume has an awn
One or more florets
there is one floret per spikelet
Lemma awn length
5–50 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
1–4 mm
Anther length
1.2–3.2 mm
Show all characteristics
  • Flowers

    Anther length
    1.2–3.2 mm
    Anther number
    Up to 3
    Awn on glume
    the glume has an awn
    Bristles below spikelets
    no
    Floret lower bract texture
    the lemma is thin and flexible
    Floret number
    1
    Floret types within spikelet
    there are at least two distinct forms of florets within one spikelet
    Glume awn length
    11–25 mm
    Glume keel
    NA
    Glume relative length
    neither glume is quite as long as all of the florets
    Glume shape
    • the glume is V-shaped in cross-section
    • the glume is flat or curved in cross-section
    Glume veins
    • 1
    • 3
    • 5
    Glumes per spikelet
    2
    Inflorescence axis orientation
    • the inflorescence axis is arched or curved outward
    • the inflorescence axis is straight
    Inflorescence branches
    • the flowers are attached to branches rather than to the main axis of the inflorescence
    • there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
    Inflorescence branches coming off the lowest stem node
    Up to 2
    Inflorescence crowding
    NA
    Inflorescence length
    30–80 mm
    Inflorescence length to width ratio
    4.3–5
    Inflorescence type (general)
    • the inflorescence is a spike, or is spike-like, lacking obvious branches
    • the spikelets are borne on stalks or on branches
    Inflorescence type (specific)
    the inflorescence has pairs (or trios) of spikelets, but with one always either missing a stalk or on a shorter stalk than the other
    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
    5–50 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 cross-section
    the lemma is flat or rounded if you cut across the midpoint
    Lemma keel hairs
    NA
    Lemma surface
    the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)
    Lemma tip
    the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)
    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)
    Lemma vein number
    5
    Lemma vein orientation
    the veins on the lemma stay roughly parallel throughout
    Lower glume relative length
    the lower glume is nearly as long, or as long as, the upper glume
    One or more florets
    there is one floret per spikelet
    Palea length
    8–15 mm
    Palea relative length
    palea is one half to fully as long as lemma
    Reproductive system
    some flowers on the plant have both carpels and stamens, while other flowers have only one type of reproductive organ (polygamous)
    Spikelet axis length
    2.5–6.5 mm
    Spikelet axis tip
    there is an extension of the spikelet axis beyond the tip of the spikelet
    Spikelet disintegration
    the spikelet breaks off below the glumes
    Spikelet pedicel
    • the spikelets do not have pedicels
    • the spikelets have pedicels
    Spikelet pedicel length
    0–1 mm
    Spikelet position
    • NA
    • the spikelets emerge mainly from the upper halves of the inflorescence branches
    Spikelet shape
    the spikelets are obovate (egg-shaped but with the widest point above the middle) in profile
    Spikelets per panicle branch
    0
    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 relative length
    the upper glume is up to 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
    Seed length
    4–5 mm
  • Growth form

    Lifespan
    the plant lives only a single year or less
  • 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
    Up to 28 cm
    Leaf blade texture
    • the leaf blade is rough and sandpapery
    • the leaf blade is smooth, or it may have soft hairs
    Leaf blade width
    2–5 mm
    Leaf ligule length
    1–4 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 overlapping and not fused together except in the basal half (or less)
    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
  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    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
    Plant height
    30–110 cm
    Stem hairs
    the stem is nearly to completely hairless
    Stem orientation
    • the stems are upright
    • the stems trail along the ground or on other plants through most or all of their length
    • the stems trail at the base, but turn upwards at the tips
    Stem spacing
    the stems grow close together in compact clusters or tufts

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

In New England

Distribution

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

Conservation status

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

ssp. leporinum

Massachusetts
not applicable (S-rank: SNA)

Subspecies and varieties

Our subspecies is Hordeum murinum L. ssp. leporinum.

From Flora Novae Angliae dichotomous key

3.  Hordeum murinum L. ssp. leporinum (Link) Arcang. E

mouse barley. Critesion murinum (L.) A. Löve var. leporinum (Link) A. Löve; Hordeum leporinum Link • CT, MA, ME. Roadsides, fields, disturbed soil.

Native to North America?

No

Sometimes confused with

Hordeum pusillum:
glumes of the central spikelet of each triad with scabrous margins; auricles absent or poorly developed and very short (vs. H. murinum, with glumes of the central spikelet of each triad with ciliate margins, and auricles present at the summit of most leaf sheaths, well-developed, up to 8 mm long).

Synonyms

  • Critesion murinum (L.) A. Löve var. leporinum (Link) A. Löve
  • Hordeum leporinum Link

Family

Poaceae

Genus

Hordeum