Carex hirta — hammer sedge
![Inflorescence: Carex hirta. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-hirta-in-ahaines.jpg)
![Leaves: Carex hirta. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-hirta-le-ahaines-c.jpg)
![Perigynia: Carex hirta. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-hirta-pe-ahaines.jpg)
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Facts
Hammer sedge is a non-native sedge, introduced from Eurasia and first collected in the United States in 1877 in Amherst, Massachusetts. It tolerates a variety of moisture levels, and as is typical for an introduced species, usually inhabits human-disturbed sites.
Habitat
Anthropogenic (human-disturbed or -maintained habitats), 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.
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enlargeCharacteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- Vermont
- stem leaf blade width
- 2.5–8 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
- Top spike
- the uppermost spike contains only staminate flowers
- Perigynium hairs
- the perigynium is hairy
- Perigynium length
- 4.8–7.8 mm
- Leaf sheath color
- the leaf sheath is tinted pink, red or purple
- Leaf blade texture
- the leaf blade is hairy
- 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
- 80–500 mm
- Length of scale
-
- the scale is nearly as long as, or longer than, the perigynium
- the scale is shorter than the perigynium
- Lowest spike length
- 20–50 mm
- Perigynium beak
- the perigynium has a beak
- Perigynium beak length
- 1.5–2.7 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
- 0.8–1.7 mm
- Perigynium color
-
- green
- orange to orange-brown
- Perigynium cross-section
-
- the perigynium is relatively round in cross-section
- the perigynium is trigonous (triangular) in cross-section
- Perigynium hairs
- the perigynium is hairy
- Perigynium length
- 4.8–7.8 mm
- Perigynium nerve number
- 12–20
- Perigynium nerve texture
- the nerves on the perigynium are raised, even after drying the perigynium
- Perigynium nerves lower side
- 6–10
- Perigynium nerves upper side
- 6–10
- 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
- 1.7–2.5 mm
- Perigynium winged
- the perigynium has no wings
- Pollen- and seed-producing spikes
- some of the spikes produce perigynia
- Pollen-producing spike length
- 20–30 mm
- Pollen-producing spike number
- 1–3
- Pollen-producing spike peduncle length
- At least 0 mm
- Scale awn
- the carpellate scale has an awn on it
- Scale awn texture
- the carpellate scale awn has tiny teeth
- Scale color
-
- green
- tan
- Scale tip
-
- the carpellate scale tip is acuminate (tapered to a narrow point)
- the carpellate scale tip is acute (has a sharp point)
- Spike on stalk
- the lowest spike on the plant has 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 acuminate (tapered to a narrow point)
- the staminate scale tip is acute (has a sharp point)
- the staminate scale tip is obtuse (has a blunt 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
- 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 flat or M-shaped, with two prominent side-veins
- Leaf blade texture
- the leaf blade is hairy
- 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 rough, or has hairs
- Ligule length
- 2–10.5 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
- 2.5–8 mm
- Lowest leaf sheath texture
- the leaf sheath feels smooth (it may have soft hairs)
- stem leaf blade width
- 2.5–8 mm
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- Vermont
- Specific habitat
-
- human-disturbed or -maintained habitats
- meadows or fields
-
Stem, shoot, branch
- Plant height
- 10–90 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
Not classified
In New England
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
19. Carex hirta L. E
hammer sedge. CT, MA, ME, VT. Fields, ditches, railroad embankments, roadsides, and other human-disturbed sites on a variety of soil moisture regimes.
Native to North America?
No
Sometimes confused with
- Carex atherodes:
- perigynia glabrous and leaf blades minutely papillose on the abaxial surface (vs. C. hirta, with perigynia pubescent and leaf blades not minutely papillose).
- Carex trichocarpa:
- leaf sheaths and blades glabrous and floral scales glabrous (vs. C. hirta, with leaf sheaths and blades pubescent and staminate and often carpellate scales pubescent).