Carex oligosperma — few-seeded sedge
![Achenes: Carex oligosperma. ~ By Jill Weber. ~ Copyright © 2025 Jill Weber. ~ jillweber03[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-oligosperma-ac-jweber.jpg)
![Leaves: Carex oligosperma. ~ By Jill Weber. ~ Copyright © 2025 Jill Weber. ~ jillweber03[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-oligosperma-le-jweber.jpg)
![Inflorescence: Carex oligosperma. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-oligosperma-in-ahaines.jpg)
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Facts
Few-seeded sedge is a sedge of bogs, acidic fens and wet meadows. The Iroquois made a decoction of this plant that they used as an emetic before running or playing lacrosse.
Habitat
Bogs, fens, meadows and fields
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.
Found this plant? Take a photo and post a sighting.
enlargeCharacteristics
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- stem leaf blade width
- 0.5–2.5 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 has a peduncle
- the lowest spike on the plant is not borne on a peduncle
- Top spike
- the uppermost spike contains only staminate flowers
- Perigynium hairs
- the perigynium has no hairs
- Perigynium length
- 4–6.7 mm
- Leaf sheath color
- the leaf sheath is tinted pink, red or purple
- 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
- Bumps on fruit
- there are no papillae on the perigynium surface
- Inflorescence length
- 30–200 mm
- Length of scale
- the scale is shorter than the perigynium
- Lowest spike length
- 10–20 mm
- Lowest spike stalk length
- At least 0 mm
- Perigynium beak
- the perigynium has a beak
- Perigynium beak length
- 0.3–0.9 mm
- Perigynium beak orientation
- the beak of the perigynium is straight, and in line with the perigynium
- Perigynium beak serrations
- the perigynium beak has no serrations
- Perigynium beak teeth
- the perigynium beak is divided at the top into two teeth
- Perigynium beak teeth length
- Up to 0.3 mm
- Perigynium color
-
- brown
- green
- tan
- 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
- Perigynium length
- 4–6.7 mm
- Perigynium nerve number
- 7–15
- Perigynium nerve texture
- the nerves on the perigynium are raised, even after drying the perigynium
- Perigynium nerves lower side
- 3–7
- Perigynium nerves upper side
- 3–7
- Perigynium orientation
- the perigynia are oriented vertically or pressed against the axis or adjacent perigynia
- Perigynium puffy
- the perigynium is inflated (there is space between the perigynium and the achene)
- Perigynium shape
- the perigynium body is ovate (egg-shaped)
- Perigynium width
- 2.5–3.4 mm
- Perigynium winged
- the perigynium has no wings
- Pollen- and seed-producing spikes
- some of the spikes produce perigynia
- Pollen-producing spike number
- 1–2
- Scale awn
- The carpellate scale does not have an awn (it may have a short point)
- Scale awn texture
- NA
- Scale color
-
- brown
- green
- Scale length
- 3.2–5.6 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 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 three branches
- Top spike
- the uppermost spike contains only staminate flowers
-
Fruits or seeds
- Achene dimples
- the achene has no folds or dimples
- Achene length
- 2–3 mm
- Style persistence
- the style stays on the mature achenes
-
Growth form
- Rhizomes
- there are long rhizomes present
-
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 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 is tinted pink, red or purple
- 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 no sheath (or a very short sheath up to four millimeters in length)
- Lowest leaf blade width
- 0.5–2.5 mm
- Lowest leaf sheath texture
- the leaf sheath feels smooth (it may have soft hairs)
- stem leaf blade width
- 0.5–2.5 mm
-
Place
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Specific habitat
-
- bogs
- fens
- meadows or fields
-
Stem, shoot, branch
- Plant height
- 30–90 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)
In New England
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- historical (S-rank: SH), special concern, extirpated (code: SC*)
- Maine
- unranked (S-rank: SNR)
- Massachusetts
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- rare to uncommon (S-rank: S2S3)
From Flora Novae Angliae dichotomous key
183. Carex oligosperma Michx. N
few-seeded sedge. CT, MA, ME, NH, VT. Bogs, acidic fens, and wet meadows.
Native to North America?
Yes
Sometimes confused with
- Carex saxatilis:
- flowers with 2 stigmas, achenes biconvex, and perigynia obscurely veined (vs. C. oligosperma, with carpellate flowers with 3 stigmas, achenes triangular in cross-section, and perigynia distinctly veined).
- Carex vesicaria:
- perigynium beak 1.1-2.6 mm long, with two evident, terminal teeth, and leaf blades flat to V-shaped, with plane margins, 1.8-6.5 mm wide (vs. C. oligosperma, with the perigynium beak 0.3–0.9 mm long, obscurely bidentate at tip, and leaf blades filiform, with involute margins, 0.5–2.5 mm wide).