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Carex cephaloidea — thin-leaved sedge

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Facts

Thin-leaved sedge is similar to several other sedges, but has very short carpellate scales half the length of the perigynia, and with a relatively congested inflorescence of 5-10 spikes.

Habitat

Floodplain (river or stream floodplains), forests

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
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
stem leaf blade width
4–8 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 carpellate flowers located below, or intermixed with, the staminate flowers
Perigynium hairs
the perigynium has no hairs
Perigynium length
3–4.5 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

    Anther length
    0.7–1.3 mm
    Bumps on fruit
    there are no papillae on the perigynium surface
    Inflorescence length
    20–40 mm
    Length of scale
    the scale is shorter than the perigynium
    Lowest spike length
    15–40 mm
    Lowest spike stalk length
    0 mm
    Lowest spike width
    8–10 mm
    Perigynium beak
    the perigynium has a beak
    Perigynium beak length
    1–1.3 mm
    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 beak teeth length
    0.2–0.5 mm
    Perigynium color
    green
    Perigynium 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
    3–4.5 mm
    Perigynium nerve number
    4–7
    Perigynium nerve texture
    • NA
    • the nerves on the perigynium are raised, even after drying the perigynium
    Perigynium nerves lower side
    4–7
    Perigynium nerves upper side
    0
    Perigynium orientation
    • the perigynia are angled outwards
    • the perigynia are oriented vertically or pressed against the axis or adjacent perigynia
    Perigynium shape
    the perigynium body is ovate (egg-shaped)
    Perigynium width
    1.5–2.5 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
    • tan
    • white or translucent
    Scale length
    1.5–2 mm
    Scale tip
    • the carpellate scale tip is acute (has a sharp point)
    • the carpellate scale tip is obtuse (has a blunt 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 carpellate flowers located below, or intermixed with, the staminate flowers
  • Fruits or seeds

    Achene dimples
    the achene has no folds or dimples
    Achene length
    1.6–2 mm
    Achene width
    1.3–1.7 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 all produced from the base of the plant
    Leaf blade cross-section
    The leaf blade is folded lengthwise, with one prominent midvien
    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 white dots on the green tissues of the leaf sheathes
    Leaf sheath folds
    the leaf sheath has corrugations on it
    Leaf sheath texture
    the leaf sheath feels smooth, and has no hairs
    Ligule length
    3–7 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
    4–8 mm
    Lowest leaf sheath texture
    the leaf sheath feels smooth (it may have soft hairs)
    stem leaf blade width
    4–8 mm
  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • forests
    • river or stream floodplains
  • Stem, shoot, branch

    Plant height
    30–120 cm
    Relative stem height
    • the main stem is equal to or shorter than the leaves
    • the main stem is taller than the leaves
    Spike internode length
    Up to 10 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

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

In New England

Distribution

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

Conservation status

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

Massachusetts
fairly widespread (S-rank: S4)
New Hampshire
rare (S-rank: S2), threatened (code: T)

From Flora Novae Angliae dichotomous key

145.  Carex cephaloidea (Dewey) Dewey N

thin-leaved sedge. Carex muricata L. var. cephaloidea Dewey; C. sparganioides Muhl. ex 
 Willd. var. cephaloidea (Dewey) Carey • CT, MA, ME, NH, VT; also reported from RI by George (1992), but specimens are unknown. Mesic, often rich, soils of upland deciduous forests 
and riparian forests.

Native to North America?

Yes

Sometimes confused with

Carex sparganioides:
inflorescence mostly 4-10 cm long, with remote lower spikes, and body of perigynium with a narrow wing 0.1-0.2 mm wide (vs. C. cephaloidea, with the inflorescence 2-4 cm long, with crowded lower spikes, and body of perigynium with a very narrow wing up to 0.1 mm wide).

Synonyms

  • Carex muricata L. var. cephaloidea Dewey
  • Carex sparganioides Muhl. ex Willd. var. cephaloidea (Dewey) Carey

Family

Cyperaceae

Genus

Carex