• You are here:
• Full Key
• Grass-like plants
• Sedges
• Carex arcta

Carex arcta — northern cluster sedge

Facts

Northern cluster sedge is found only in the northern New England states, and it is listed as endangered in Vermont. It is typically found in wet-mesic, mixed or evergreen forests. The tightly-aggregated inflorescence of 5-15 spikes is characteristic.

Habitat

Forests, shores of rivers or lakes

Characteristics

• Flowers

  Bumps on fruit

  the perigynium surface has papillae on it

  Inflorescence length

  15–40 mm

  Length of scale

  the scale is shorter than the perigynium

  Lowest spike length

  5–10 mm

  Lowest spike stalk length

  0 mm

  Lowest spike width

  4–6 mm

  Perigynium beak

  the perigynium has a beak

  Perigynium beak length

  0.75–1.25 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 color

  brown

  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

  2–3.5 mm

  Perigynium nerve texture

  the nerves on the perigynium are raised, even after drying the perigynium

  Perigynium nerves upper side

  At least 0

  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

  1.25–1.5 mm

  Perigynium winged

  the perigynium has no wings

  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

  • brown
  • green
  • white or translucent

  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

  Staminate scale tip

  • the staminate scale tip is acute (has a sharp point)
  • the staminate scale tip is obtuse (has a blunt point)

  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

  1.25–1.51 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 flat or M-shaped, with two prominent side-veins

  Leaf blade length to width ratio

  75–125

  Leaf blade texture

  the leaf blade is smooth and hairless, or rough and sandpapery

  Leaf blade width

  2–4 mm

  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
  • 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 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

  2–4 mm

  Lowest leaf sheath texture

  the leaf sheath feels smooth (it may have soft hairs)

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Maine
  • New Hampshire
  • Vermont

  Specific habitat

  • forests
  • shores of rivers or lakes

• Stem, shoot, branch

  Plant height

  15–80 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

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

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae