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- Cyperaceae
- Eriophorum
- Eriophorum viridicarinatum
Eriophorum viridicarinatum — green-keeled cottongrass, green-keeled cottonsedge
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Facts
Green-keeled cottonsedge inhabits fens and meadows throughout New England, wherever the pH is high. It gets its common name from the fact that the floral scales have a prominent green midrib. This species is endemic to North America, ranging from Alaska to Newfoundland; it comes close to its southern range limit in New England, which is why it is listed as rare in Rhode Island.
Habitat
Fens (calcium-rich wetlands), 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.
Found this plant? Take a photo and post a sighting.
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
- Leaf blade width
- 2–6 mm
- Leaf blade cross-section
-
- the leaf blade is flat or rolled in at the edges
- the leaf blade is triangular in cross-section
- 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 hairs
- the fruit is like a seed, and surrounded by scales
- Fruit length
- 2.5–3.5 mm
- Leaf position on plant
- some leaf attachment points are above the midpoint of the stem
- Perianth composition
- there are bristles attached at the base of the achene
- Fruit cross-section
- the fruit is triangular to terete (circular) in cross-section
-
Flowers
- Anther length
- 0.8–2 mm
- Floral bristle color
- the bristles are white
- Floral bristle number
- 8 or more
- Floral bristle relative length
- the bristles are longer than the achene
- Floral bristles
- the bristles are straight or slightly curved
- Floral scale hairs
- there are no hairs on the floral scales
- Floral scale length
- 4–6 mm
- Floral scale nerves
- 1
- Floral scale shape
-
- the floral scales are lanceolate (widest below the middle, and tapering at both ends)
- the floral scales are ovate (roughly egg-shaped)
- Floral scale translucent
- the floral scales are opaque
- 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 at least somewhat spread out, with at least one branch coming from the main stem
- Inflorescence position
- the inflorescence is at the tip of the plant
- Inflorescence shape
- the aggregations within the inflorescence are roughly circular (not flattened) in cross-section
- Inflorescence type
- there are two or more flowers, spikes or flower clusters on a branched inflorescence
- Perianth composition
- there are bristles attached at the base of the achene
- Stamen number
- 3
- Stigma number
- 3
- Style division
- the top two thirds of the style is divided
- floral bristle barbs
- the bristles do not have barbs on them
-
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
- 2.5–3.5 mm
- Fruit type (general)
-
- the fruit is like a seed, and surrounded by hairs
- 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
- the leaf blade is triangular in cross-section
- Leaf blade length
- Up to 300 mm
- Leaf blade width
- 2–6 mm
- Leaf form
- all the leaves hold their form out of water
- Leaf position on plant
- some leaf attachment points are above the midpoint of the stem
- 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
- the plant has ligules at the leaf blade bases
- Stem leaf blades
- there are fully-developed leaves with leaf blades on the main stem
-
Place
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- fens (calcium-rich wetlands)
- meadows or fields
-
Stem, shoot, branch
- Plant height
- 20–90 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
- 0.9–1.2 mm
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
In New England
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)
- Rhode Island
- extremely rare (S-rank: S1), concern (code: C)
From Flora Novae Angliae dichotomous key
6. Eriophorum viridicarinatum (Engelm.) Fern. N
green-keeled cottonsedge. Eriophorum latifolium Hoppe var. viridicarinatum Engelm. • CT, MA, ME, NH, RI, VT. Fens and high-pH meadows.
Native to North America?
Yes
Sometimes confused with
Synonyms
- Eriophorum latifolium Hoppe var. viridicarinatum Engelm.