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• True grasses
• Danthonia compressa

Danthonia compressa — flattened oatgrass

Facts

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

• 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

From the dichotomous key of Flora Novae Angliae