Carex foenea — straw sedge
![Inflorescence: Carex foenea. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/carex-foenea-in-ahaines.jpg)
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Facts
Very similar to silvery-flowered sedge (Carex argyrantha), straw sedge differs in having curved, rather than straight and parallel veins on the perigynia. Straw sedge typically has fewer spikes per inflorescence (3 - 7) whereas silvery-flowered sedge typically has more than 7 spikes per inflorescence.
Habitat
Anthropogenic (man-made or disturbed habitats), cliffs, balds, or ledges, meadows and fields, woodlands
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
- New Hampshire
- Rhode Island
- Vermont
- stem leaf blade width
- 2–4 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
- the uppermost spike contains both staminate and carpellate flowers, with the staminate flowers located below the carpellate flowers
- Perigynium hairs
- the perigynium has no hairs
- Perigynium length
- 3.3–5 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
- Bumps on fruit
- there are no papillae on the perigynium surface
- Inflorescence length
- 15–80 mm
- Length of scale
- the scale is nearly as long as, or longer than, the perigynium
- Lowest spike length
- 7–25 mm
- Lowest spike stalk length
- 0 mm
- Lowest spike width
- 5–7 mm
- Perigynium beak
- the perigynium has a beak
- 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 planoconvex (flat on one surface and rounded on the other) in cross-section
- Perigynium hairs
- the perigynium has no hairs
- Perigynium length
- 3.3–5 mm
- Perigynium nerve number
- 4–17
- Perigynium nerve texture
- the nerves on the perigynium are raised, even after drying the perigynium
- Perigynium nerves lower side
- 4–9
- Perigynium nerves upper side
- 0–8
- Perigynium orientation
- the perigynia are oriented vertically or pressed against the axis or adjacent perigynia
- Perigynium puffy
- the achene is tightly enclosed by the perigynium
- Perigynium shape
- the perigynium body is ovate (egg-shaped)
- Perigynium width
- 1.5–2.5 mm
- Perigynium winged
- the perigynium has wings on it
- 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)
- Scale awn texture
- NA
- Scale color
-
- brown
- green
- other
- red-brown
- Scale length
- 4–5 mm
- 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 is not borne on a peduncle
- Spike orientation
- the spikes are bent downwards or droop downwards
- Spikes per stem
- 2-15
- Staminate scale tip
- the staminate scale tip is acuminate (tapered to a narrow point)
- Stigma branching
- the stigmas have two branches
- Top spike
- the uppermost spike contains both staminate and carpellate flowers, with the staminate flowers located below the carpellate flowers
-
Fruits or seeds
- Achene dimples
- the achene has no folds or dimples
- Achene length
- 1.3–2.1 mm
- Achene width
- 1.2–1.7 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
- 40–75
- 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
- the top edge of the leaf sheath has papillae on it
- Leaf sheath color
- the leaf sheath has no pink, red or purple tinting
- Leaf sheath dots
- there are white dots on the green 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
- 2–3 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
- 2–4 mm
- Lowest leaf sheath texture
- the leaf sheath feels smooth (it may have soft hairs)
- stem leaf blade width
- 2–4 mm
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- cliffs, balds, or ledges
- man-made or disturbed habitats
- meadows or fields
- woodlands
-
Stem, shoot, branch
- Plant height
- 20–120 cm
- Relative stem height
- the main stem is taller than the leaves
- Spike internode length
- 5–25 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 non-wetlands. (Wetland indicator code: UPL)
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
- extremely rare (S-rank: S1), special concern (code: SC)
- Maine
- unranked (S-rank: SNR)
- Massachusetts
- fairly widespread (S-rank: S4)
- Vermont
- rare (S-rank: S2), endangered (code: E)
From Flora Novae Angliae dichotomous key
46. Carex foenea Willd. N
straw sedge. Carex aenea Fern. • CT, MA, ME, NH, RI, VT. Woodlands, cliffs, sandy fields, and open, disturbed soil.
Native to North America?
Yes
Sometimes confused with
- Carex argyrantha:
- perigynia granular-papillose, with usually 5-8 +/- parallel veins on the adaxial surface, and carpellate scales white-green (vs. C. foenea, with perigynia smooth, without veins or with 4-8 curving veins on the adaxial surface, and carpellate scales red-brown to green or gold-brown).
- Carex praticola:
- beak of perigynium cylindric and unwinged in the apical 0.4-1 mm, and achenes 0.8-1.1 mm wide (vs. C. foenea, with beak of perigynium flat, winged, and minutely serrulate at the apex, and achenes 1.2-1.6 mm wide).
Synonyms
- Carex aenea Fern.