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- Carex sterilis
Carex sterilis — dioecious sedge
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New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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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, meadows and fields, shores of rivers or lakes, swamps
Characteristics
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- Rhode Island
- Vermont
- stem leaf blade width
- 1.2–2.6 mm
- Lowest bract sheath
- the lowest bract has no sheath (or a very short sheath up to four millimeters in length)
- Spike on stalk
- the lowest spike on the plant is not borne on a peduncle
- Top spike
-
- entirely carpellate
- the uppermost spike contains only staminate flowers
- Perigynium hairs
- the perigynium has no hairs
- Perigynium length
- 2.1–3.8 mm
- Leaf sheath color
- the leaf sheath has no pink, red or purple tinting
- 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
-
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 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)
- stem leaf blade width
- 1.2–2.6 mm
-
Place
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- Rhode Island
- Vermont
- Specific habitat
-
- fens
- 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
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.
- Connecticut
- uncommon (S-rank: S3), special concern (code: SC)
- Maine
- uncommon (S-rank: S3), special concern (code: SC)
- Massachusetts
- rare (S-rank: S2), threatened (code: T)
- Rhode Island
- historical (S-rank: SH), state historical (code: SH)
- Vermont
- extremely rare (S-rank: S1)
Native to North America?
Yes
Sometimes confused with
- Carex echinata:
- plants monoecious, at the last the uppermost spike clearly bisexual, and anthers 0.8-1.6 mm long (vs. C. sterilis, the plants subdioecious, the spikes all or nearly all of a single sex on each stem, and anthers mostly 1.2-2.2 mm long).
- Carex interior:
- plants monoecious, at the last the uppermost spike clearly bisexual, and anthers 0.6-1.4 mm long (vs. C. sterilis, the plants subdioecious, the spikes all or nearly all of a single sex on each stem, and anthers mostly 1.2-2.2 mm long).
Synonyms
- Carex elachycarpa Fern.
- Carex muricata L. var. sterilis (Fern.) Gleason
- Kobresia elachycarpa (Fern.) Fern.
Family
Genus
From the dichotomous key of Flora Novae Angliae
175. Carex sterilis Willd. NC
dioecious sedge. Carex elachycarpa Fern.; C. muricata L. var. sterilis (Fern.) Gleason; Kobresia elachycarpa (Fern.) Fern. • CT, MA, ME, RI, VT. Fens, river shore seeps, and wet meadows.