Eleocharis aestuum — tidal spikesedge
![Plant form: Eleocharis aestuum. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/eleocharis-aestuum-ha-ahaines-b.jpg)
![Flowers and fruits: Eleocharis aestuum. ~ 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/eleocharis-aestuum-ff-efarnsworth.jpg)
![Inflorescences: Eleocharis aestuum. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Cyperaceae/eleocharis-aestuum-in-ahaines-c.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
Tidal spikesedge is restricted to freshwater tidal river communities on the east coast of the United States. Within New England it is found in Connecticut, Maine and Vermont. It may be confused with Wright's spikesedge (Eleocharis diandra).
Habitat
Brackish or salt marshes and flats, floodplain (river or stream floodplains), fresh tidal marshes or flats, shores of rivers or lakes
Characteristics
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Vermont
- Stem shape in cross-section
- the stem is round or oval in cross-section
- Leaf blade width
- 0 mm
- Leaf blade cross-section
- NA
- Inflorescence position
- the inflorescence is at the tip of the plant
- Inflorescence branching
- the inflorescence is on one or more stems with no branches
- Fruit type (general)
- the fruit is like a seed, and surrounded by scales
- Fruit length
- 0.75–1 mm
- Leaf position on plant
- the attachment points of all the leaves are at or near the base of the plant
- Perianth composition
-
- there are bristles attached at the base of the achene
- there is no perianth on the plant
- Fruit cross-section
- the fruit is biconvex or elliptic (widest in the middle and tapering to both ends) in cross-section
-
Flowers
- Anther length
- 0.3–0.5 mm
- Floral bristle color
- the bristles are pale brown to brown
- Floral bristle number
-
- 0
- 1-4
- Floral bristle relative length
-
- NA
- the bristles are between one tenth as long as the achene, and equal in length to 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
- 1.5–2 mm
- Floral scale nerves
- 1
- Floral scale shape
- the floral scales are ovate (roughly egg-shaped)
- Floral scale translucent
- the floral scales are translucent
- Flower number per cluster
- 1
- Inflorescence bract angle
- NA
- Inflorescence bract number
- NA
- Inflorescence bract position (Sparganium)
- NA
- Inflorescence bracts
- NA
- Inflorescence branching
- the inflorescence is on one or more stems with no branches
- Inflorescence crowding
-
- NA
- 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 roughly circular (not flattened) in cross-section
- Inflorescence type
- there is one spike or raceme at the tip of the stem
- Perianth composition
-
- there are bristles attached at the base of the achene
- there is no perianth on the plant
- Stamen number
- 2
- Stigma number
- 2
- Style division
- the top two thirds of the style is divided
- floral bristle barbs
- the bristles do not have barbs on them
- plantlets budding at flower bases
-
- no
- yes
-
Fruits or seeds
- Achene beak length
- 0 mm
- Achene surface texture
- the achene is smooth (it has no detectable texture)
- Achene tubercle relative width
- the tubercle is one half to two thirds as wide as the achene
- Achene tubercle width
- 0.24–0.45 mm
- Capsule relative length
- NA
- Fruit cross-section
- the fruit is biconvex or elliptic (widest in the middle and tapering to both ends) in cross-section
- Fruit length
- 0.75–1 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) with a tubercle (a swelling or projection, usually of a different color or texture) on it
- Locules in capsule
- NA
- Seed length
- 0 mm
- Seed tail relative length
- 0 mm
- Seed tails
- NA
- Tubercle height
- 0.2–0.3 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
- NA
- Leaf blade length
- 0 mm
- Leaf blade width
- 0 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
- NA
- Leaf sheath hairs
- the leaf sheathes are without hairs
- Pedicel length (Typha)
- 0 mm
- Stem leaf blade ligules
- NA
- Stem leaf blades
- there are no leaves on the main stem, or there is a small tooth or tiny blade, or a leaf sheath with no blade
- Width of seed-producing inflorescence
- 2–4 mm
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Vermont
- Specific habitat
-
- brackish or salt marshes and flats
- fresh tidal marshes or flats
- river or stream floodplains
- shores of rivers or lakes
-
Stem, shoot, branch
- Plant height
- 3–30 cm
- Stem shape in cross-section
- the stem is round or oval in cross-section
- Stem texture near tip
- the stem feels smooth near the tip
- Stem thickness at midpoint
- 0.5–1 mm
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
New England distribution and conservation status
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- absent
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- unranked (S-rank: SNR)
- Maine
- rare (S-rank: S2), special concern (code: SC)
- Vermont
- extremely rare (S-rank: S1)
Native to North America?
Yes
Sometimes confused with
- Eleocharis diandra:
- floral scales acute and keeled near the apex and tubercles 0.1-0.2 mm tall (vs. E. aestuum, with floral scales rounded and unkeeled at the apex and tubercles 0.2-0.3 mm tall).
- Eleocharis ovata:
- tubercles 2/3 as wide as the achene body or wider and flowers usually with three stamens (vs. E. aestuum, with tubercles 1/2 to 2/3 as wide as the achene body and flowers usually with 2 stamens).
Synonyms
- Eleocharis ovata (Roth) Roemer & J.A. Schultes var. aphanactis Moore
- Eleocharis pallidostachys D.M. Hines, nomen nudum
Family
Genus
From the dichotomous key of Flora Novae Angliae
2. Eleocharis aestuum A. Haines NC
tidal spikesedge. Eleocharis ovata (Roth) Roemer & J.A. Schultes var. aphanactis Moore; E. pallidostachys D.M. Hines, nomen nudum • CT, ME, VT. Tidal river shores on sand, silt, and mud substrate, rarely on inland lakes with altered hydrology. Previous reports of Eleocharis diandra from ME were based on this recently described species.