Carex adusta Boott

swarthy sedge

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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

Swarthy sedge is distributed across Canada and some northern states of the United States. It grows in dry, sandy soils of woodlands, road shoulders and old road beds in Maine and New Hampshire.

Habitat

Anthropogenic (man-made or disturbed habitats), woodlands

Characteristics

Habitat
terrestrial
New England state
  • Maine
  • New Hampshire
stem leaf blade width
2–3.5 mm
Lowest bract sheath
the lowest bract has no sheath (or a very short sheath up to four millimeters in length)
Spike on stalk
the lowest spike on the plant is not borne on a peduncle
Top spike
the uppermost spike contains both staminate and carpellate flowers, with the staminate flowers located below the carpellate flowers
Perigynium hairs
the perigynium has no hairs
Perigynium length
4–5 mm
Leaf sheath color
the leaf sheath has no pink, red or purple tinting
Leaf blade texture
the leaf blade is smooth and hairless, or rough and sandpapery
Perigynium beak teeth
the perigynium beak is divided at the top into two teeth
Show All Characteristics
  • Flowers
    Bumps on fruit
    there are no papillae on the perigynium surface
    Inflorescence length
    20–45 mm
    Length of scale
    the scale is nearly as long as, or longer than, the perigynium
    Lowest spike length
    8–11 mm
    Lowest spike stalk length
    0 mm
    Lowest spike width
    5–8 mm
    Perigynium beak
    the perigynium has a beak
    Perigynium beak orientation
    the beak of the perigynium is straight, and in line with the perigynium
    Perigynium beak serrations
    the perigynium beak has tiny serrations along the edges
    Perigynium beak teeth
    the perigynium beak is divided at the top into two teeth
    Perigynium color
    • green
    • tan
    • yellow
    Perigynium cross-section
    • the perigynium is biconvex (convexly rounded on both sides, like a lens) in cross-section
    • the perigynium is planoconvex (flat on one surface and rounded on the other) in cross-section
    Perigynium hairs
    the perigynium has no hairs
    Perigynium length
    4–5 mm
    Perigynium nerve number
    7–13
    Perigynium nerve texture
    the nerves on the perigynium are raised, even after drying the perigynium
    Perigynium nerves lower side
    7–11
    Perigynium nerves upper side
    0–2
    Perigynium orientation
    • the perigynia are angled outwards
    • the perigynia are oriented vertically or pressed against the axis or adjacent perigynia
    Perigynium puffy
    the achene is tightly enclosed by the perigynium
    Perigynium shape
    the perigynium body is ovate (egg-shaped)
    Perigynium width
    1.9–2.5 mm
    Perigynium winged
    the perigynium has wings on it
    Pollen- and seed-producing spikes
    some of the spikes produce perigynia
    Pollen-producing spike length
    0 mm
    Pollen-producing spike number
    0
    Pollen-producing spike peduncle length
    0 mm
    Pollen-producing spike width
    0 mm
    Scale awn
    The carpellate scale does not have an awn (it may have a short point)
    Scale awn texture
    NA
    Scale color
    red-brown
    Scale length
    4–5.5 mm
    Scale tip
    the carpellate scale tip is acute (has a sharp point)
    Spike on stalk
    the lowest spike on the plant is not borne on a peduncle
    Spike orientation
    the spikes are oriented vertically or pressed against the axis
    Spikes per stem
    2-15
    Stigma branching
    the stigmas have two branches
    Top spike
    the uppermost spike contains both staminate and carpellate flowers, with the staminate flowers located below the carpellate flowers
  • Fruits or seeds
    Achene dimples
    the achene has no folds or dimples
    Achene length
    2.1–2.5 mm
    Achene width
    1.6–2 mm
    Style persistence
    the style falls off the mature achenes
  • Growth form
    Rhizomes
    there are no rhizomes, or the rhizomes are very short
  • Leaves
    Leaf arrangement
    the leaves are mostly produced higher up on the plant
    Leaf blade cross-section
    The leaf blade is folded lengthwise, with one prominent midvien
    Leaf blade length to width ratio
    35–71
    Leaf blade texture
    the leaf blade is smooth and hairless, or rough and sandpapery
    Leaf bumps
    the upper surface of the leaf blade does not have papillae
    Leaf sheath bumps
    there are no papillae at the top edge of the leaf sheath
    Leaf sheath color
    the leaf sheath has no pink, red or purple tinting
    Leaf sheath dots
    there are no dots on the leaf sheathes
    Leaf sheath folds
    there are no corrugations on the leaf sheath
    Leaf sheath texture
    the leaf sheath feels smooth, and has no hairs
    Ligule length
    1–4 mm
    Lowest bract sheath
    the lowest bract has no sheath (or a very short sheath up to four millimeters in length)
    Lowest leaf blade width
    2–3.5 mm
    Lowest leaf sheath texture
    the leaf sheath feels smooth (it may have soft hairs)
    stem leaf blade width
    2–3.5 mm
  • Place
    Habitat
    terrestrial
    New England state
    • Maine
    • New Hampshire
    Specific habitat
    • man-made or disturbed habitats
    • woodlands
  • Stem, shoot, branch
    Plant height
    25–80 cm
    Relative stem height
    the main stem is taller than the leaves
    Spike internode length
    2–15 mm
    Stem cross-section
    the main stem is roughly triangular in cross-section
    Stem spacing
    the stems grow close together in compact clusters or tufts

Wetland Status

Not classified

New England Distribution and Conservation Status

Distribution

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

Conservation Status

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

Maine
rare (S-rank: S2), endangered (code: E)
New Hampshire
historical (S-rank: SH), endangered (code: E)

Native to North America?

Yes

Sometimes Confused With

Carex foenea:
carpellate scales narrower than the perigynia they subtend and achenes 1.2-1.6 mm wide (vs. C. adusta, with carpellate scales as wide as the perigynia they subtend and achenes 1.6-2 mm wide).

Family

Cyperaceae

Genus

Carex

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Information from Dichotomous Key of Flora Novae Angliae

34.  Carex adusta Boott NC

swarthy sedge. ME, NH. Sandy, often well-drained, soils of woodlands, road shoulders, 
old road beds, and borrow pits.