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Aristida longespica — red threeawn

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Facts

Red threeawn is a small and delicate grass of sandy and disturbed soils. Two varieties are found in New England. The more widespread is the native variety (Aristida longespica var. geniculata), occurring throughout New England, except in Maine. The less widespread variety (A. longespica var. longespica), is found in Connecticut and Massachusetts, and is considered introduced, although it is native to other parts of North America.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields, shores of rivers or lakes, woodlands

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
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf blade width
1–2 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
3–4 mm
Glume relative length
one or 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
1–27 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
Up to 0.5 mm
Anther length
0.2–4 mm
Show all characteristics
  • Flowers

    Anther length
    0.2–4 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 relative length
    one or both glumes are as long or longer than all of the florets
    Glume veins
    1
    Glumes per spikelet
    2
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    the inflorescence axis is straight
    Inflorescence branch length
    1–4 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 crowding
    • the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
    • the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    60–220 mm
    Inflorescence length to width ratio
    3.7–6
    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 branched, and the branches do NOT both grow from the same side of the plant AND look like spikes
    Inflorescence width
    10–60 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 straight or twisted, but not coiled one half turn
    Lemma awn length
    1–27 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
    Up to 1 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 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
    2–11 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
    3–4 mm
    Spikelet number per node
    0
    Spikelets per panicle branch
    2–5
    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
    2–11 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
    3–4 mm
  • Growth form

    Horizontal rooting stem
    no
    Lifespan
    the plant lives only a single year or less
    Rhizomes
    no
    Roots
    there are only slender roots on the plant
  • 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 length
    5–14 cm
    Leaf blade width
    1–2 mm
    Leaf ligule length
    Up to 0.5 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
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
    • shores of rivers or lakes
    • woodlands
  • Stem, shoot, branch

    Plant height
    15–65 cm
    Stem spacing
    the stems grow close together in compact clusters or tufts

Wetland status

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

In New England

Distribution

Connecticut
present
Maine
absent
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.

var. geniculata

Connecticut
uncommon (S-rank: S3), special concern (code: SC)
Massachusetts
not applicable (S-rank: SNA)
New Hampshire
rare (S-rank: S2), threatened (code: T)
Rhode Island
rare (S-rank: S2), concern (code: C)
Vermont
extremely rare (S-rank: S1)

var. longespica

Connecticut
widespread (S-rank: S5)
Massachusetts
not applicable (S-rank: SNA)

From Flora Novae Angliae dichotomous key

3.  Aristida longespica Poir. n

red threeawn. 3a. Aristida geniculata Raf.; Aristida intermedia Scribn. & Ball;  3b. Aristida gracilis Ell. • CT, MA, NH, RI, VT. Sandy fields, roadsides, woodland openings, disturbed sandy soils, sandy pond shores.

1a.  Central awn (8–) 12–27 mm long; lateral awns (1–) 6–18 mm long; glumes 4–11 mm long; flowers with 1 or 3 anthers … 3a. A. longespica var. geniculata (Raf.) Fern.

1b.  Central awn 1–10 (–14) mm long; lateral awns 0–5 (–8) mm long; glumes 2–8 mm long; flowers with 1 anther … 3b. A. longespica var. longespica

Variety geniculata is native and known from CT, MA, NH, RI, VT. Variety longespica is non-native and known from CT, MA.

Native to North America?

Yes

Sometimes confused with

Aristida basiramea:
central awn coiled at base 2 to 3 full turns and flowers with 3 anthers ca. 3 mm long (vs. A. longespica, with central awn not coiled at base and flowers either with 1 anther that is 0.2-0.3 mm long or 3 anthers that are 3-4 mm long).

Synonyms

  • Aristida gracilis Ell.

Family

Poaceae

Genus

Aristida