Danthonia compressa Austin ex Peck

flattened oatgrass

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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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Facts About

Flattened oatgrass is native to eastern North America, and fairly common in New England, found in forest edges and openings, trail edges, logging roads, and less frequently in fields. It is reported to inhibit establishment of tree seedlings when it establishes in openings within disturbed forests.

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
2–4 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
7–16 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
6–10 mm
Anther length
Up to 2.2 mm
Show All Characteristics
  • Flowers
    Anther length
    Up to 2.2 mm
    Anther number
    3
    Awn on glume
    the glume has no awn
    Glume relative length
    both glumes are as long or longer than all of the florets
    Glume veins
    • 3
    • 5
    • 7 or more
    Inflorescence arrangement
    the spikelets are uniform
    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
    Inflorescence length
    50–100 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
    Lemma awn base
    the awn is attached right at the tip of the lemma
    Lemma awn coiled
    the lemma awn is coiled at least one half turn
    Lemma awn length
    6–10 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 cross-section
    the lemma is flat or rounded if you cut across the midpoint
    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 vein number
    7 or more
    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
    Spikelet axis tip
    there is an extension of the spikelet axis beyond the tip of the spikelet
    Spikelet length
    7–16 mm
    Spikelets spiny
    the spikelets do not appear spiny
    Upper glume shape
    the upper glume is widest at or below the middle
  • Leaves
    Leaf auricles
    the leaves do not have auricles
    Leaf blade cross-section
    the leaf blade is more or less flat in cross-section, or slightly folded or rolled inwards
    Leaf blade width
    2–4 mm
    Leaf ligule type
    the leaf ligule is in the form of fine hairs
    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 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
    Stem spacing
    the stems grow close together in compact clusters or tufts

Wetland Status

Occurs most often in non-wetlands, but rarely 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)

Native to North America?

Yes

Sometimes Confused With

Danthonia spicata

Synonyms

  • Danthonia alleni Austin

Family

Poaceae

Genus

Danthonia

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Information from Dichotomous Key of Flora Novae Angliae

2.  Danthonia compressa Austin ex Peck N

Flattened oatgrass. Danthonia alleni Austin • CT, MA, ME, NH, RI, VT; throughout. Forest edges and openings, edges of shaded trails, old logging road beds, uncommonly in old pastures and fields.