Your help is appreciated. We depend on donations to help keep this site free and up to date for you. Can you please help us?

Donate

Native Plant Trust: Go Botany Discover thousands of New England plants

Carex mitchelliana — Mitchell's sedge

Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.

Facts

Mitchell's sedge is found in deciduous and evergreen swamps, marshes, stream banks and shores in Massachusetts and Rhode Island. New England is the northern limit of its range, but it is uncommon throughout its range, being known from less than 100 extinct and extant populations.

Habitat

Marshes, shores of rivers or lakes, swamps

New England distribution

Adapted from BONAP data

Found this plant? Take a photo and post a sighting.

North America distribution

Adapted from BONAP data

enlarge

Characteristics

Habitat
wetlands
New England state
  • Massachusetts
  • Rhode Island
stem leaf blade width
3–8 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 has a peduncle
Top spike
the uppermost spike contains only staminate flowers
Perigynium hairs
the perigynium has no hairs
Perigynium length
2.5–3.9 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 not divided at the tip into two teeth, or the teeth are very tiny
Show all characteristics

  • Flowers

    Bumps on fruit
    the perigynium surface has papillae on it
    Lowest spike length
    31–79 mm
    Lowest spike stalk length
    6–30 mm
    Lowest spike width
    3.6–7.4 mm
    Perigynium beak
    the perigynium has a beak
    Perigynium beak length
    0.1–0.3 mm
    Perigynium beak orientation
    the beak of the perigynium is straight, and in line with the perigynium
    Perigynium beak serrations
    the perigynium beak has no serrations
    Perigynium beak teeth
    the perigynium beak is not divided at the tip into two teeth, or the teeth are very tiny
    Perigynium beak teeth length
    0 mm
    Perigynium color
    tan
    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
    2.5–3.9 mm
    Perigynium nerve number
    0–5
    Perigynium nerve texture
    • NA
    • the nerves on the perigynium are raised, even after drying the perigynium
    Perigynium nerves lower side
    0–5
    Perigynium nerves upper side
    0
    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
    1.3–2.1 mm
    Perigynium winged
    the perigynium has no wings
    Pollen- and seed-producing spikes
    some of the spikes produce perigynia
    Pollen-producing spike length
    Up to 50 mm
    Pollen-producing spike number
    1–2
    Scale awn
    the carpellate scale has an awn on it
    Scale awn texture
    the carpellate scale awn has tiny teeth
    Scale color
    • brown
    • red-brown
    • tan
    Scale length
    2.9–6.3 mm
    Scale tip
    the carpellate scale tip is rounded to retuse (blunt or rounded, with a notch at the tip)
    Spike on stalk
    the lowest spike on the plant has a peduncle
    Spike orientation
    the spikes are bent downwards or droop downwards
    Spikes per stem
    2-15
    Stigma branching
    the stigmas have two 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 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 length to width ratio
    43–44
    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 rough, or has 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
    3–8 mm
    Lowest leaf sheath texture
    the leaf sheath feels rough
    stem leaf blade width
    3–8 mm

  • Place

    Habitat
    wetlands
    New England state
    • Massachusetts
    • Rhode Island
    Specific habitat
    • marshes
    • shores of rivers or lakes
    • swamps

  • Stem, shoot, branch

    Plant height
    40–140 cm
    Relative stem height
    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 close together in compact clusters or tufts

Wetland status

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

In New England

Distribution

Connecticut
absent
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.

Massachusetts
rare (S-rank: S2), threatened (code: T)
Rhode Island
extremely rare (S-rank: S1), concern (uncertain) (code: C*)

From Flora Novae Angliae dichotomous key

137.  Carex mitchelliana M.A. Curtis NC

Mitchell’s sedge. Carex crinita Lam. var. mitchelliana (M.A. Curtis) Gleason • MA, RI. Swamps, both deciduous and evergreen types, stream banks, shorelines, and graminoid marshes.

Native to North America?

Yes

Sometimes confused with

Carex gynandra:
perigynia smooth to weakly papillose and achenes with a constriction (vs. C. mitchelliana, with perigynia densely papillose and achenes without a constriction).
Carex crinita:
lower leaf sheaths smooth and perigynia smooth to weakly papillose (vs. C. mitchelliana, with the lower leaf sheaths scabrous due to minute, stiff hairs and perigynia densely papillose).

Synonyms

  • Carex crinita Lam. var. mitchelliana (M.A. Curtis) Gleason

Family

Cyperaceae

Genus

Carex