Arrhenatherum elatius (L.) J. & K. Presl

tall oat grass

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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At Concord

The subspecies in Concord is ssp. elatius.

Facts About

Tall oat grass is a non-native species that is invasive in some parts of the United States. There are two subspecies, one of which (Arrhenatherum elatius ssp. elatius) is widespread in New England, while the other (Arrhenatherum elatius ssp. bulbosum) is found only in Massachusetts.

Habitat

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

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf blade width
1–10 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
7–11 mm
Glume relative length
both glumes are as long or longer than 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
10–20 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
1–3 mm
Anther length
3.6–6 mm
Show All Characteristics
  • Flowers
    Anther length
    3.6–6 mm
    Anther number
    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
    2
    Floret types within spikelet
    there are at least two distinct forms of florets within one spikelet
    Glume awn length
    0 mm
    Glume keel
    the glume keels are rough or hairy
    Glume relative length
    both glumes are as long or longer than all of the florets
    Glume shape
    the glume is V-shaped in cross-section
    Glume veins
    • 1
    • 3
    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
    1.5–2 cm
    Inflorescence branches
    the flowers are attached to branches rather than to the main axis of the inflorescence
    Inflorescence crowding
    the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    70–360 mm
    Inflorescence length to width ratio
    3.6–7
    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
    10–100 mm
    Inforescence position
    the spikelets are mainly carried at the end of the stem
    Lemma awn base
    the awn is attached at the upper half of the lemma
    Lemma awn coiled
    the lemma awn is straight or twisted, but not coiled one half turn
    Lemma awn length
    10–20 mm
    Lemma awn number
    the lemma has one awn on it
    Lemma awn orientation
    the awn of the lemma on dried or older plants is curved or bent outwards
    Lemma base hair length
    Up to 3.7 mm
    Lemma base hairs
    the lemma has hairs at the base
    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 narrow point (it may or may not also have an awn or teeth at the tip)
    Lemma vein number
    • 3
    • 5
    • 7 or more
    Lower glume length
    4–7 mm
    Lower glume relative length
    the lower glume is one third to three quarters as long as the upper glume
    One or more florets
    there is more than one floret per spikelet
    Palea length
    3–9.5 mm
    Palea relative length
    palea is one half to fully as long as lemma
    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
    7–11 mm
    Spikelet number per node
    0
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet pedicel length
    1–10 mm
    Spikelet position
    the spikelets emerge from both the upper and lower halves of the inflorescence branches
    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
    7–10 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
    Seed length
    4–5 mm
  • Growth form
    Horizontal rooting stem
    no
    Lifespan
    the plant lives more than two years
    Rhizomes
    • no
    • yes
    Roots
    • the plant has rhizomes (horizontal underground stem with roots growing from it)
    • there are only slender roots on the plant
  • Leaves
    Leaf auricles
    the leaves do not have auricles
    Leaf basal lobe hairy
    NA
    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
    Leaf blade length
    5–32 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
    1–10 mm
    Leaf ligule length
    1–3 mm
    Leaf ligule type
    the leaf ligule is in the form of a membrane with fine hairs
    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
    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
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • edges of forests
    • 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
    50–180 cm
    Stem hairs
    the stem is nearly to completely hairless
    Stem orientation
    the stems are upright
    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)

New England Distribution and Conservation Status

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
unranked (S-rank: SNR)

var. bulbosum

Massachusetts
unranked (S-rank: SNR)

var. elatius

Massachusetts
unranked (S-rank: SNR)

Native to North America?

No

Sometimes Confused With

Avenula pubescens

Synonyms

  • Avena elatior L.

Family

Poaceae

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