Cyperus houghtonii — Houghton's flatsedge
![Flowers and fruits: Cyperus houghtonii. ~ By William Larkin. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/cyperus-houghtonii-ff-wlarkin.jpg)
![Inflorescences: Cyperus houghtonii. ~ By William Larkin. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/cyperus-houghtonii-in-wlarkin.jpg)
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Facts
Houghton's flatsedge is a rare native flatsedge of dry sandy sites and ledges, including roadsides, lakeshores, sandplains and woodlands. It is found in Massachusetts, Maine, New Hampshire and Vermont. At least half the historic populations appear to have died out.
Habitat
Anthropogenic (man-made or disturbed habitats), ridges or ledges, shores of rivers or lakes, 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.
Found this plant? Take a photo and post a sighting.
enlargeCharacteristics
- Habitat
- terrestrial
- New England state
-
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Stem shape in cross-section
- the stem is roughly triangular in cross-section
- Leaf blade width
- 1–6 mm
- Leaf blade cross-section
- the leaf blade is flat or rolled in at the edges
- Inflorescence position
- the inflorescence is at the tip of the plant
- Inflorescence branching
- the inflorescence is branched
- Fruit type (general)
- the fruit is like a seed, and surrounded by scales
- Fruit length
- 1.5–2 mm
- Leaf position on plant
- the attachment points of all the leaves are at or near the base of the plant
- Perianth composition
- there is no perianth on the plant
- Fruit cross-section
- the fruit is triangular to terete (circular) in cross-section
-
Flowers
- Anther length
- 0.5–0.7 mm
- Floral bristle color
- NA
- Floral bristle number
- 0
- Floral bristle relative length
- NA
- Floral bristles
- NA
- Floral scale hairs
- there are no hairs on the floral scales
- Floral scale length
- 1.8–2.6 mm
- Floral scale nerves
- 7 or more
- Floral scale shape
- the floral scales are orbicular (circular in outline)
- Floral scale translucent
- the floral scales are opaque
- Flower number per cluster
-
- 2-5
- 5-20
- Inflorescence bract angle
- the bracts are vertical or angled only slightly outwards
- Inflorescence bract number
- there are two to five bracts per inflorescence
- Inflorescence bract position (Sparganium)
- NA
- Inflorescence bracts
- there are at least two bracts, and they are either flat or folded or rolled in at the edges
- Inflorescence branching
- the inflorescence is branched
- Inflorescence crowding
- the inflorescence is crowded together in one tight cluster
- Inflorescence position
- the inflorescence is at the tip of the plant
- Inflorescence shape
- the aggregations within the inflorescence are at least somewhat flattened in cross-section
- Inflorescence type
- there are two or more flowers, spikes or flower clusters on a branched inflorescence
- Perianth composition
- there is no perianth on the plant
- Stamen number
- 3
- Stigma number
- 3
- Style division
- the top two thirds of the style is divided
- floral bristle barbs
- NA
- plantlets budding at flower bases
- no
-
Fruits or seeds
- Achene tubercle relative width
- NA
- Achene tubercle width
- 0 mm
- Capsule relative length
- NA
- Fruit cross-section
- the fruit is triangular to terete (circular) in cross-section
- Fruit length
- 1.5–2 mm
- Fruit type (general)
- the fruit is like a seed, and surrounded by scales
- Fruit type (specific)
- the fruit is an achene (dry, seed-like fruit) without a tubercle (a swelling or projection, usually of a different color or texture)
- Locules in capsule
- NA
- Seed length
- 0 mm
- Seed tail relative length
- 0 mm
- Seed tails
- NA
- Tubercle height
- 0 mm
-
Growth form
- Lifespan
- the plant lives more than two years
- Underground organs
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
-
Leaves
- Auricle length
- 0 mm
- Auricle texture
- NA
- Auricles
- there are no auricles on the leaf sheath
- Leaf blade cross-section
- the leaf blade is flat or rolled in at the edges
- Leaf blade length
- 120–300 mm
- Leaf blade width
- 1–6 mm
- Leaf form
- all the leaves hold their form out of water
- Leaf position on plant
- the attachment points of all the leaves are at or near the base of the plant
- Leaf septa
- the leaf blades do not have transverse septa
- Leaf sheath hairs
- the leaf sheathes are without hairs
- Pedicel length (Typha)
- 0 mm
- Stem leaf blade ligules
- there are no ligules at the leaf blade bases
- Stem leaf blades
- there are fully-developed leaves with leaf blades on the main stem
- Width of seed-producing inflorescence
- 8–20 mm
-
Place
- Habitat
- terrestrial
- New England state
-
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Specific habitat
-
- man-made or disturbed habitats
- ridges or ledges
- shores of rivers or lakes
- woodlands
-
Stem, shoot, branch
- Plant height
- 5–50 cm
- Stem shape in cross-section
- the stem is roughly triangular in cross-section
- Stem texture near tip
- the stem feels smooth near the tip
Wetland status
Not classified
In New England
Distribution
- Connecticut
- absent
- 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.
- Maine
- historical (S-rank: SH), potentially extirpated (code: PE)
- Massachusetts
- extremely rare (S-rank: S1), endangered (code: E)
- New Hampshire
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- rare (S-rank: S2), threatened (code: T)
From Flora Novae Angliae dichotomous key
12. Cyperus houghtonii Torr. NC
Houghton’s flatsedge. MA, ME, NH, VT. Dry-mesic to xeric sands and ledges, including roadsides, lake shores, sandplains, and woodlands.
Native to North America?
Yes
Sometimes confused with
- Cyperus lupulinus:
- floral scales ovate-elliptic, involucral bracts spreading to reflexed, and achenes with flat or slightly concave faces, mostly 1.8-2.1 times as long as wide (vs. C. houghtonii, with floral scales suborbicular, involucral bracts weakly ascending, and achenes with 1 or more evidently concave faces mostly 1.3-1.5 times as long as wide).