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• Carex flava

Carex flava — yellow-green sedge

Facts

Yellow-green sedge may get its name from the perigynia (coverings of the seeds), which have a yellow body and a green or yellow beak. It is an obligate wetland species that prefers high-pH sites.

Habitat

Meadows and fields, ridges or ledges, shores of rivers or lakes

Characteristics

• Flowers

  Anther length

  1–2.1 mm

  Bumps on fruit

  there are no papillae on the perigynium surface

  Length of scale

  the scale is shorter than the perigynium

  Lowest spike length

  8–22 mm

  Lowest spike stalk length

  At least 0 mm

  Lowest spike width

  7.5–12.7 mm

  Perigynium beak

  the perigynium has a beak

  Perigynium beak length

  1.3–2.7 mm

  Perigynium beak orientation

  the beak of the perigynium is curved, or angled out from 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

  Up to 0.5 mm

  Perigynium color

  yellow

  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

  4–6.3 mm

  Perigynium nerve number

  At least 10

  Perigynium nerve texture

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

  Perigynium nerves lower side

  At least 5

  Perigynium nerves upper side

  At least 5

  Perigynium orientation

  the perigynia are curved or bent downwards or backwards along the axis

  Perigynium puffy

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

  Perigynium shape

  • the perigynium body is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
  • the perigynium body is ovate (egg-shaped)

  Perigynium width

  1–1.9 mm

  Perigynium winged

  the perigynium has no wings

  Pollen- and seed-producing spikes

  some of the spikes produce perigynia

  Pollen-producing spike length

  9–22 mm

  Pollen-producing spike number

  1–2

  Pollen-producing spike peduncle length

  0.4–9 mm

  Pollen-producing spike width

  1.1–3 mm

  Scale awn

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

  Scale awn texture

  • NA
  • the carpellate scale awn does not have teeth (it may or may not have hairs)

  Scale color

  red-brown

  Scale length

  2.3–3.9 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
  • the lowest spike on the plant is not borne on a peduncle

  Spike orientation

  • the spikes are angled outwards, or arched over
  • 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 carpellate flowers located below, or intermixed with, the staminate flowers
  • the uppermost spike contains only staminate flowers

• Fruits or seeds

  Achene dimples

  the achene has no folds or dimples

  Achene length

  1.3–1.7 mm

  Achene width

  0.9–1.2 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 folded lengthwise, with one prominent midvien

  Leaf blade length to width ratio

  31–52

  Leaf blade texture

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

  Leaf blade width

  1.6–5.8 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

  Lowest bract sheath

  • the lowest bract has a sheath longer than four millimeters
  • the lowest bract has no sheath (or a very short sheath up to four millimeters in length)

  Lowest leaf blade width

  1.6–5.8 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
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • meadows or fields
  • ridges or ledges
  • shores of rivers or lakes

• Stem, shoot, branch

  Plant height

  10–75 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