Eleocharis aestuum A. Haines

tidal spikesedge

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

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
Show All Characteristics
  • 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

Cyperaceae

Genus

Eleocharis

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Information from 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 nudumCT, 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.