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- Dichotomous Key
- Cyperaceae
- Cyperus
- Cyperus bipartitus
Cyperus bipartitus — shining flatsedge
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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.
Found this plant? Take a photo and post a sighting.
Facts
Shining flatsedge is found in moist to wet shorelines throughout New England; although native to most of our area, some populations in Rhode Island may have been introduced. The seeds produced by the flowers inside copper-colored scales may be eaten by some birds.
Habitat
Shores of rivers or lakes, wetland margins (edges of wetlands)
Characteristics
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Stem shape in cross-section
-
- the stem is roughly triangular in cross-section
- the stem is round or oval in cross-section
- Leaf blade width
- 1–2 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
- 1–1.5 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 lenticular (lens-shaped) in cross-section
-
Flowers
- Anther length
- 0.4–0.5 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
- 1.9–2.7 mm
- Floral scale nerves
- 2-5
- Floral scale shape
-
- the floral scales are oblong (rectangular but with rounded ends)
- the floral scales are ovate (roughly egg-shaped)
- 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 at least somewhat spread out, with at least one branch coming from the main stem
- 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
-
- 2
- 3
- Stigma number
- 2
- 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 beak length
- 0 mm
- Achene surface texture
- the achene has very tiny 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 lenticular (lens-shaped) in cross-section
- Fruit length
- 1–1.5 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 only a single year or less
- Rhizome thickness
- 0 mm
- Underground organs
- there are only slender roots on the plant
-
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
- 10–80 mm
- Leaf blade width
- 1–2 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
- 7–14 mm
-
Place
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- edges of wetlands
- shores of rivers or lakes
-
Stem, shoot, branch
- Plant height
- 3–30 cm
- Stem shape in cross-section
-
- the stem is roughly triangular in cross-section
- the stem is round or oval in cross-section
- Stem texture near tip
- the stem feels smooth near the tip
Wetland status
Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)
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.
- Massachusetts
- unranked (S-rank: SNR)
Native to North America?
Yes
Sometimes confused with
Synonyms
- Cyperus rivularis Kunth
- Pycreus rivularis (Kunth) Palla
Family
Genus
From the dichotomous key of Flora Novae Angliae
2. Cyperus bipartitus Torr. N
shining flatsedge. Cyperus rivularis Kunth; Pycreus rivularis (Kunth) Palla • CT, MA, ME, NH, RI, VT. Moist to wet, usually sandy, shorelines.