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• Carex Group 1
• Section Stellulatae
• Carex sterilis

Carex sterilis — dioecious sedge

Facts

Dioecious sedge is nearly always dioecious (having male and female reproductive structures on separate plants). This is a species of conservation concern chiefly because of the rarity of the calcareous fens in which it grows.

Habitat

Fens (calcium-rich wetlands), meadows and fields, shores of rivers or lakes, swamps

Characteristics

• Flowers

  Anther length

  1–2.35 mm

  Bumps on fruit

  there are no papillae on the perigynium surface

  Distance between perigynia

  3.8–15.5 mm

  Length of scale

  the scale is nearly as long as, or longer than, the perigynium

  Lowest spike length

  3–13.5 mm

  Lowest spike stalk length

  0 mm

  Lowest spike width

  4.5–7.2 mm

  Perigynium beak

  the perigynium has a beak

  Perigynium beak length

  0.65–1.6 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

  0.15–0.5 mm

  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

  2.1–3.8 mm

  Perigynium nerve number

  5–22

  Perigynium nerve texture

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

  Perigynium nerves lower side

  5–12

  Perigynium nerves upper side

  0–10

  Perigynium orientation

  • the perigynia are angled outwards
  • the perigynia are curved or bent downwards or backwards along the axis

  Perigynium shape

  • the perigynium body is ovate (egg-shaped)
  • the perigynium body is triangular, widest near the base

  Perigynium width

  1.2–2.2 mm

  Perigynium winged

  the perigynium has no wings

  Pollen- and seed-producing spikes

  • all the spikes produce only pollen
  • some of the spikes produce perigynia

  Pollen-producing spike length

  3.5–13.7 mm

  Pollen-producing spike number

  0–1

  Pollen-producing spike peduncle length

  At least 0 mm

  Pollen-producing spike width

  1.2–2.6 mm

  Scale awn

  The carpellate scale does not have an awn (it may have a short point)

  Scale awn texture

  NA

  Scale color

  red-brown

  Scale length

  1.8–2.9 mm

  Scale tip

  the carpellate scale tip is acute (has a sharp 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)

  Stigma branching

  the stigmas have two branches

  Top spike

  • entirely carpellate
  • the uppermost spike contains only staminate flowers

• Fruits or seeds

  Achene dimples

  the achene has no folds or dimples

  Achene length

  1–1.7 mm

  Achene width

  0.9–1.3 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 folded lengthwise, with one prominent midvien

  Leaf blade length to width ratio

  63–96

  Leaf blade texture

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

  Leaf blade width

  1.2–2.6 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

  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

  Ligule length

  0.3–1.7 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

  1.2–2.6 mm

  Lowest leaf sheath texture

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

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • Vermont

  Specific habitat

  • fens (calcium-rich wetlands)
  • meadows or fields
  • shores of rivers or lakes
  • swamps

• Stem, shoot, branch

  Plant height

  10–75 cm

  Relative stem height

  the main stem is taller than the leaves

  Spike internode length

  9–40 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

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

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae