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Carex schweinitzii — Schweinitz's sedge

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Facts

Schweinitz's sedge only comes into New England along the western edges of Connecticut, Massachusetts and Vermont, in open calcareous swamps, marshes and streamsides. Although uncommon and local, it can form large stands where it occurs.

Habitat

Fens, marshes, shores of rivers or lakes, swamps

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
wetlands
New England state
  • Connecticut
  • Massachusetts
  • Vermont
stem leaf blade width
4–11 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 has a peduncle
Top spike
the uppermost spike contains only staminate flowers
Perigynium hairs
the perigynium has no hairs
Perigynium length
4.2–7 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
    80–240 mm
    Length of scale
    • the scale is nearly as long as, or longer than, the perigynium
    • the scale is shorter than the perigynium
    Lowest spike length
    30–80 mm
    Lowest spike width
    10–15 mm
    Perigynium beak
    the perigynium has a beak
    Perigynium beak length
    1.4–2.4 mm
    Perigynium beak orientation
    the beak of the perigynium is straight, and in line with the perigynium
    Perigynium beak serrations
    the perigynium beak has no serrations
    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
    • tan
    • yellow
    Perigynium cross-section
    • the perigynium is relatively round in cross-section
    • the perigynium is trigonous (triangular) in cross-section
    Perigynium hairs
    the perigynium has no hairs
    Perigynium length
    4.2–7 mm
    Perigynium nerve number
    7–11
    Perigynium nerve texture
    the nerves on the perigynium are raised, even after drying the perigynium
    Perigynium nerves lower side
    3–5
    Perigynium nerves upper side
    3–5
    Perigynium orientation
    the perigynia are oriented vertically or pressed against the axis or adjacent perigynia
    Perigynium puffy
    the perigynium is inflated (there is space between the perigynium and the achene)
    Perigynium shape
    the perigynium body is ovate (egg-shaped)
    Perigynium width
    1.3–1.8 mm
    Perigynium winged
    the perigynium has no wings
    Pollen- and seed-producing spikes
    some of the spikes produce perigynia
    Pollen-producing spike number
    1–2
    Pollen-producing spike peduncle length
    At least 0 mm
    Scale awn
    the carpellate scale has an awn on it
    Scale awn texture
    the carpellate scale awn has tiny teeth
    Scale color
    • brown
    • white or translucent
    Scale length
    2.4–6.9 mm
    Scale tip
    the carpellate scale tip is acuminate (tapered to a narrow point)
    Spike on stalk
    the lowest spike on the plant has a peduncle
    Spike orientation
    • the spikes are angled outwards, or arched over
    • the spikes are oriented vertically or pressed against the axis
    Spikes per stem
    2-15
    Staminate scale tip
    • the staminate scale tip is acuminate (tapered to a narrow point)
    • the staminate scale tip is acute (has a sharp point)
    Stigma branching
    the stigmas have three branches
    Top spike
    the uppermost spike contains only staminate flowers

  • Fruits or seeds

    Achene dimples
    the achene has no folds or dimples
    Style persistence
    the style stays on the mature achenes

  • Growth form

    Rhizomes
    there are long rhizomes present

  • Leaves

    Leaf arrangement
    the leaves are mostly produced higher up on the plant
    Leaf blade cross-section
    the leaf blade is flat or M-shaped, with two prominent side-veins
    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
    Lowest bract sheath
    the lowest bract has no sheath (or a very short sheath up to four millimeters in length)
    Lowest leaf blade width
    4–11 mm
    Lowest leaf sheath texture
    the leaf sheath feels smooth (it may have soft hairs)
    stem leaf blade width
    4–11 mm

  • Place

    Habitat
    wetlands
    New England state
    • Connecticut
    • Massachusetts
    • Vermont
    Specific habitat
    • fens
    • marshes
    • shores of rivers or lakes
    • swamps

  • Stem, shoot, branch

    Plant height
    18–65 cm
    Relative stem height
    • the main stem is equal to or shorter than the leaves
    • the main stem is taller than the leaves
    Stem cross-section
    the main stem is roughly triangular in cross-section
    Stem spacing
    the stems grow singly or a few together (they may form diffuse colonies)

Wetland status

Occurs only in wetlands. (Wetland indicator code: OBL)

In New England

Distribution

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

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
extremely rare (S-rank: S1), endangered (code: E)
Rhode Island
historical (S-rank: SH), state historical (code: SH)
Vermont
rare (S-rank: S2)

From Flora Novae Angliae dichotomous key

188.  Carex schweinitzii Dewey ex Schwein. NC

Schweinitz’s sedge. CT, MA, VT; western New England. Open wetlands in regions of high-pH bedrock, including fens, graminoid marshes, stream borders, and open swamps.

181×188. Carex hystericina × Carex schweinitzii → This very rare sedge hybrid is known from MA, VT. It generally resembles Carex schweinitzii but has conspicuous anthocyanic coloration on the lower leaf sheaths, shorter rhizomes (these extending as much as 6–8 cm before turning upward to produce a new aerial shoot), perigynia with ca. 10–16 nerves, and staminate scales with some marginal cilia on the body of the scale. In contrast, C. schweinitzii has non-anthocyanic lower sheaths, rhizomes up to ca. 30 cm long (or longer), perigynia with 7–11 nerves, and no marginal cilia on the staminate scales. Carex hystericina has strongly anthocyanic lower sheaths, rhizomes rarely longer than 3 cm, perigynia with 13–21 nerves, and prominently ciliate staminate scales.

Native to North America?

Yes

Sometimes confused with

Carex hystericina:
stems cespitose with short rhizomes, perigynia with 12-21 veins, and at least some of the staminate scales with scabrous awns (vs. C. schweinitzii, with stems produced singly or a few together from elongate rhizomes, perigynia with 7-11 veins, and staminate scales acute to acuminate at the apex or sometimes the lowermost scales with a short awn tip).

Family

Cyperaceae

Genus

Carex