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Carex debilis — white-edged sedge

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Facts

White-edged sedge is extremely variable in appearance. There are two distinct varieties in our region, Carex debilis var. rudgei, found throughout New England, and C. debilis var. debilis, comparatively rare and known only from Connecticut, Massachusetts and Rhode Island.

Habitat

Anthropogenic (man-made or disturbed habitats), floodplain (river or stream floodplains), forest edges, forests, meadows and fields, shores of rivers or lakes

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
  • Rhode Island
  • Vermont
stem leaf blade width
2–7 mm
Lowest bract sheath
the lowest bract has a sheath longer than four millimeters
Spike on stalk
the lowest spike on the plant has a peduncle
Top spike
  • the uppermost spike contains both staminate and carpellate flowers, with the staminate flowers located below the carpellate flowers
  • the uppermost spike contains only staminate flowers
Perigynium hairs
  • the perigynium has no hairs
  • the perigynium is hairy
Perigynium length
5–9.5 mm
Leaf sheath color
the leaf sheath is tinted pink, red or purple
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
    Length of scale
    the scale is shorter than the perigynium
    Lowest spike length
    25–80 mm
    Lowest spike stalk length
    Up to 50 mm
    Lowest spike width
    2–3 mm
    Perigynium beak
    the perigynium has a beak
    Perigynium beak length
    0.7–2 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
    Up to 1 mm
    Perigynium color
    green
    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
    • the perigynium is hairy
    Perigynium length
    5–9.5 mm
    Perigynium nerve number
    12–22
    Perigynium nerve texture
    the nerves on the perigynium are raised, even after drying the perigynium
    Perigynium nerves lower side
    6–11
    Perigynium nerves upper side
    6–11
    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 elliptic (widest near the middle and tapering at both ends)
    Perigynium width
    1.1–2.2 mm
    Perigynium winged
    the perigynium has no wings
    Pollen- and seed-producing spikes
    some of the spikes produce perigynia
    Pollen-producing spike length
    15–50 mm
    Pollen-producing spike number
    0–1
    Pollen-producing spike peduncle length
    15–50 mm
    Pollen-producing spike width
    0.6–1.2 mm
    Scale awn
    The carpellate scale does not have an awn (it may have a short point)
    Scale awn texture
    NA
    Scale color
    • green
    • white or translucent
    Scale length
    2.8–6 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 has a peduncle
    Spike orientation
    • the spikes are bent downwards or droop downwards
    • the spikes are oriented vertically or pressed against the axis
    Spikes per stem
    2-15
    Staminate scale tip
    the staminate scale tip is obtuse (has a blunt point)
    Stigma branching
    the stigmas have three branches
    Top spike
    • the uppermost spike contains both staminate and carpellate flowers, with the staminate flowers located below the carpellate flowers
    • the uppermost spike contains only staminate flowers

  • Fruits or seeds

    Achene dimples
    the achene has no folds or dimples
    Achene length
    1.9–2.5 mm
    Achene width
    1–1.5 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 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 is tinted pink, red or purple
    Leaf sheath dots
    there are red dots on the translucent tissues of 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
    • the leaf sheath feels smooth, and has no hairs
    Lowest bract sheath
    the lowest bract has a sheath longer than four millimeters
    Lowest leaf blade width
    2–7 mm
    Lowest leaf sheath texture
    the leaf sheath feels smooth (it may have soft hairs)
    stem leaf blade width
    2–7 mm

  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • edges of forests
    • forests
    • man-made or disturbed habitats
    • meadows or fields
    • river or stream floodplains
    • shores of rivers or lakes

  • Stem, shoot, branch

    Plant height
    25–100 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 close together in compact clusters or tufts

Wetland status

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

In New England

Distribution

Connecticut
present
Maine
present
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.

Maine
unranked (S-rank: SNR)

var. debilis

Massachusetts
unranked (S-rank: SNR)
Rhode Island
extremely rare (S-rank: S1), concern (uncertain) (code: C*)

var. rudgei

Massachusetts
widespread (S-rank: S5)

Subspecies and varieties

Variety debilis is known from CT, MA, ME, RI. Variety rudgei is known from CT, MA, ME, NH, RI, VT.

From Flora Novae Angliae dichotomous key

90.  Carex debilis Michx. N

white-edged sedge.  90a. Carex debilis Michx. var. intercursa Fern.;  90b. Carex debilis Michx. var. allegheniensis Mackenzie; C. debilis Michx. var. interjecta Bailey; C. debilis Michx. var. strictior Bailey; C. flexuosa Muhl. ex Willd. • CT, MA, ME, NH, RI, VT. Forest edges and openings, trailsides, meadows, and open riparian banks and forests.

1a.  Perigynia 5.5–9.5 mm long, fusiform, very gradually tapering to the apex; carpellate 
scales blunt to acute at apex (rarely cuspidate), with white or pale, hyaline margins 
 … 90a. C. debilis var. debilis

1b.  Perigynia 5–6.2 mm long, narrow-ellipsoid, relatively more abruptly tapering to apex; carpellate scales acute to cuspidate (to shortly awned), with hyaline margins that are usually streaked or suffused with red-brown … 90b. C. debilis var. rudgei Bailey

Variety rudgei is known from CT, MA, ME, NH, RI, VT. It is the common form of this species found throughout most of New England. Variety debilis is relatively rare and known only from CT, 
MA, RI. Rare forms of Carex debilis var. rudgei have erect spikes (the “strictior” form; rather than arching or drooping spikes).

90b ×161. This rare sedge hybrid is known from MA. It can be separated from Carex debilis by the sparse pubescence on the perigynia and the ± absence of perigynium beak teeth. It differs from C. virescens in its short perigynium beak (vs. beak absent), sparser perigynium pubescence, longer perigynia, and less densely flowered spikes.

Native to North America?

Yes

Sometimes confused with

Carex arctata:
perigynia 3-5 mm long and achene not elevated within the perigynium (vs. C. debilis, with perigynia 5-9.5 mm long and achene elevated on a short stipe within the perigynium).

Family

Cyperaceae

Genus

Carex