Cyperus lupulinus — Great Plains flatsedge
![Flowers and fruits: Cyperus lupulinus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-ff-ahaines-a.jpg)
![Flowers and fruits: Cyperus lupulinus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-ff-ahaines-e.jpg)
![Stems and sheaths: Cyperus lupulinus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-ss-ahaines-d.jpg)
![Inflorescences: Cyperus lupulinus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-macilentus-in-ahaines-b.jpg)
![Inflorescences: Cyperus lupulinus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-macilentus-in-ahaines-c.jpg)
![Inflorescences: Cyperus lupulinus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-marcilentus-in-ahaines.jpg)
![Inflorescences: Cyperus lupulinus. ~ By Elizabeth Farnsworth. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/cyperus-lupulinus-in-efarnsworth.jpg)
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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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enlargeFacts
Great Plains flatsedge prefers open fields, roadsides and disturbed areas on sandy, well-drained soil. There are two subspecies in New England.
Habitat
Anthropogenic (man-made or disturbed habitats), grassland, meadows and fields
Characteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Stem shape in cross-section
- the stem is roughly triangular in cross-section
- Leaf blade width
- 1–3.5 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
- 1.7–2.2 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
- 0.3–1 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
- 1.8–4 mm
- Floral scale nerves
- 7 or more
- Floral scale shape
-
- the floral scales are elliptic (widest in the middle and tapering toward each end)
- the floral scales are ovate (roughly egg-shaped)
- Floral scale translucent
- the floral scales are translucent
- Flower number per cluster
-
- 2-5
- 5-20
- more than 20
- Inflorescence bract angle
- the bracts are angled outwards near horizontal or reflexed downwards
- 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 surface texture
- the achene has very obvious pits or depressions on it
- 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
- 1.7–2.2 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)
- the plant has one or more swollen storage organs underground, such as bulbs or tubers
-
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
- 50–400 mm
- Leaf blade width
- 1–3.5 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
- 12–35 mm
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- grasslands
- man-made or disturbed habitats
- meadows or fields
-
Stem, shoot, branch
- Plant height
- 3–50 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
- Stem thickness at midpoint
- 0.4–1.2 mm
Wetland status
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
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.
ssp. lupulinus
- Massachusetts
- fairly widespread (S-rank: S4)
- Vermont
- historical (S-rank: SH)
ssp. macilentus
- Massachusetts
- widespread (S-rank: S5)
Native to North America?
Yes
Sometimes confused with
- Cyperus grayi:
- involucral bracts ascending to sometimes spreading-ascending, smooth or weakly scabrous-margined, and anthers 0.7-1 mm long (vs. C. lupulinus, with involucral bracts mostly spreading to reflexed, scabrous-margined, numbering 2-4 per cluster, and anthers 0.3-0.6 mm long).
- Cyperus houghtonii:
- 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 (vs. C. lupulinus, with 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).
Synonyms
- Cyperus filiculmis Vahl var. macilentus Fern.
Family
Genus
From the dichotomous key of Flora Novae Angliae
14. Cyperus lupulinus (Spreng.) Marcks N
Great Plains flatsedge. 14a. Cyperus filiculmis Vahl; 14b. Cyperus filiculmis Vahl var. macilentus Fern.; C. lupulinus (Spreng.) Marcks ssp. macilentus (Fern.) Marcks • CT, MA, ME, NH, RI, VT. Open, well-drained, usually sandy soils of fields, roadsides, grasslands, and waste places.
1a. Spikelets 8–16 mm long, with 5–22 floral scales that are green-yellow to stramineous and 2.5–4 mm long; anthers 0.6–1 mm long; spikelets 3–4 mm thick … 14a. C. lupulinus var. lupulinus
1b. Spiklets 3–7 mm long, with 3–7 floral scales that are pale green to light red-brown and 1.8–2.5 mm long; anthers 0.3–0.6 mm long; spikelets 2.5–3.5 mm thick … 14b. C. lupulinus var. macilentus (Fern.) A. Haines
Variety lupulinus is known from CT, MA, RI, VT. Variety macilentus is known from CT, MA, ME, NH, RI, VT.
14×20. Cyperus lupulinus × Cyperus schweinitzii → Cyperus ×mesochorus Geise is a very rare flatsedge hybrid known from MA. It typically has fewer inflorescence branches than Cyperus schweinitzii (that species usually with 3–5 elongate branches), widely ascending inflorescence bracts (rather than horizontally spreading to reflexed in C. lupulinus and erect to narrowly ascending in C. schweinitzii), and floral scales with an awn tip 0.4–0.5 mm long (rather than 0.05–0.2 mm in C. lupulinus and 0.1–1 mm in C. schweinitzii).