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• Carex diandra

Carex diandra — lesser tussock sedge

Facts

Lesser tussock sedge is uncommon to rare in New England, occuring mainly in fens and open swamps on floating peat mats, and on lake shores. It requires high light and probably does not compete well with taller sedges or other vegetation.

Habitat

Fens (calcium-rich wetlands), marshes, shores of rivers or lakes, swamps

Characteristics

• Flowers

  Bumps on fruit

  there are no papillae on the perigynium surface

  Inflorescence length

  20–60 mm

  Length of scale

  the scale is shorter than the perigynium

  Lowest spike stalk length

  0 mm

  Perigynium beak

  the perigynium has a beak

  Perigynium beak length

  0.9–1.1 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
  • green

  Perigynium cross-section

  the perigynium is biconvex (convexly rounded on both sides, like a lens) in cross-section

  Perigynium hairs

  the perigynium has no hairs

  Perigynium length

  2–2.9 mm

  Perigynium nerve texture

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

  Perigynium nerves lower side

  6–10

  Perigynium orientation

  the perigynia are angled outwards

  Perigynium puffy

  the perigynium is inflated (there is space between the perigynium and the achene)

  Perigynium shape

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

  Perigynium width

  1–1.4 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)
  • the carpellate scale has an awn on it

  Scale awn texture

  • NA
  • the carpellate scale awn has tiny teeth

  Scale color

  • brown
  • tan

  Scale length

  1.5–2.7 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

  Stigma branching

  the stigmas have two branches

  Top spike

  the uppermost spike contains both staminate and carpellate flowers, with the carpellate flowers located below, or intermixed with, the staminate flowers

• Fruits or seeds

  Achene dimples

  the achene has no folds or dimples

  Achene length

  1.4–1.7 mm

  Achene width

  0.7–1 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

  140–188

  Leaf blade texture

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

  Leaf blade width

  1–2.5 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

  Ligule length

  8–57 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

  1–2.5 mm

  Lowest leaf sheath texture

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

• Place

  Habitat

  wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

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

• Stem, shoot, branch

  Plant height

  1–90 cm

  Relative stem height

  the main stem is taller than the leaves

  Spike internode length

  3–10 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