Aristida purpurascens Poir.

arrow-feather threeawn

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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

Arrow-feather threeawn is a rare plant of New England coastal sandplains, being found in Connecticut, Massachusetts and Rhode Island. This is one of a number of rare plants that colonize disturbed areas within coastal sandplain habitat, such as fire lanes and trails. These species are vulnerable to both development and natural succession, which begs the question, what type of habitat existed historically that could have supported these species? The answer may lie in natural widlfire cycles that maintained successional mosaics in fire-prone habitats before modern fire suppression.

Habitat

Anthropogenic (man-made or disturbed habitats), grassland, meadows and fields, woodlands

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Massachusetts
  • Rhode Island
Leaf blade width
1–3 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
Spikelet length
7–10 mm
Glume relative length
both glumes are as long or longer than all of the florets
Awn on glume
  • the glume has an awn
  • the glume has no awn
One or more florets
there is one floret per spikelet
Lemma awn length
8–25 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
0.2–0.3 mm
Anther length
1–1.5 mm
Show All Characteristics
  • Flowers
    Anther length
    1–1.5 mm
    Anther number
    1–3
    Awn on glume
    • the glume has an awn
    • the glume has no awn
    Bristles below spikelets
    no
    Floret lower bract texture
    the lemma is hard and firm
    Floret number
    1
    Floret types within spikelet
    all the florets within a spikelet are similar
    Glume awn length
    Up to 1 mm
    Glume keel
    • the glume keels are rough or hairy
    • the glume keels are smooth and hairless
    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
    Glumes per spikelet
    2
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    the inflorescence axis is straight
    Inflorescence branch length
    1–5 cm
    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 length
    150–550 mm
    Inflorescence length to width ratio
    18.3–30
    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 is a raceme (a long unbranched stem with stalked flowers growing along it)
    • the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes
    Inflorescence width
    5–30 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 coiled at least one half turn
    Lemma awn length
    8–25 mm
    Lemma awn number
    the lemma has more than 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 hairs
    the lemma has hairs at the base
    Lemma base length
    0.4–0.8 mm
    Lemma cross-section
    the lemma is flat or rounded if you cut across the midpoint
    Lemma hairs
    the lemma is hairless between the veins
    Lemma keel hairs
    the keel of the lemma is hairless
    Lemma marginal vein hairs
    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 a simple point, with or without an awn (long narrow extension ending in a point)
    Lemma vein number
    3
    Lower glume length
    5–10 mm
    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 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 no 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
    7–10 mm
    Spikelets per panicle branch
    1–8
    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
    5–10 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
    3–5 mm
  • Growth form
    Horizontal rooting stem
    no
    Lifespan
    the plant lives more than two years
    Rhizomes
    no
  • Leaves
    Basal leaves
    the plant has few or no leaves coming from the base of the flowering stem
    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
    10–25 cm
    Leaf blade width
    1–3 mm
    Leaf ligule length
    0.2–0.3 mm
    Leaf ligule type
    the leaf ligule is in the form of 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 color and persistence
    the leaf sheathes are off-white to light-brown and mostly persist in older leaves
    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
    • Massachusetts
    • Rhode Island
    Specific habitat
    • grasslands
    • man-made or disturbed habitats
    • meadows or fields
    • woodlands
  • Stem, shoot, branch
    Plant height
    40–100 cm
    Stem orientation
    the stems are upright
    Stem spacing
    the stems grow close together in compact clusters or tufts
    Stem thickness at base
    1–4 mm

Wetland Status

Occurs only in non-wetlands. (Wetland indicator code: UPL)

New England Distribution and Conservation Status

Distribution

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

Conservation Status

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

Connecticut
extremely rare (S-rank: S1), endangered (code: E)
Massachusetts
rare (S-rank: S2), threatened (code: T)

var. purpurascens

Massachusetts
unranked (S-rank: SNR)
Rhode Island
extremely rare (S-rank: S1), state threatened (code: ST)

Native to North America?

Yes

Sometimes Confused With

Aristida purpurea:
lower glume 4-7 mm long and usually less than 75% as long as the upper glume, and lemmas 7-13 mm long, with a callus 0.5-1.8 mm long (vs. A. purpurascens, with lower glume 5-10 mm long and usually more than 75% as long as the upper glume, and lemmas 4-8 mm long, with a callus 0.4-0.8 mm long).

Synonyms

  • Aristida purpurascens Poir. var. minor Vasey

Family

Poaceae

Genus

Aristida

Notes on Subspecies and Varieties in New England

Our variety is Aristida purpurascens Poir. var. purpurascens.

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Information from Dichotomous Key of Flora Novae Angliae

5.  Aristida purpurascens Poir. var. purpurascens NC

arrow-feather threeawn. Aristida purpurascens Poir. var. minor Vasey • CT, MA, RI. Sandy fields, roadsides, woodland openings, grasslands.