Eleocharis diandra C. Wright

Wright's 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

Wright's spikesedge is a rare plant that occurs on sandy shores of only three rivers in New England (the Androscoggin, Connecticut and Merrimack Rivers), plus Lake Champlain. It is one of the smaller, spreading spikesedges in our area, with thin, soft, reclining stems topped by plump spikelets with orange-brown flower scales and achenes with flattened tubercles. It is threatened by ATV traffic and other trampling in its muddy shoreline habitats.

Habitat

Floodplain (river or stream floodplains), shores of rivers or lakes

Characteristics

Habitat
wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • 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
0.7–1 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
  • the fruit is lenticular (lens-shaped) in cross-section
Show All Characteristics
  • Flowers
    Anther color (dry)
    the anthers range in color from white to tan or yellow to yellow-brown
    Anther length
    0.2–0.3 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
    1–1.5 mm
    Floral scale nerves
    1
    Floral scale shape
    the floral scales are ovate (roughly egg-shaped)
    Floral scale translucent
    the floral scales are opaque
    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
    • the fruit is lenticular (lens-shaped) in cross-section
    Fruit length
    0.7–1 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
    0.1–0.2 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
    1–4 mm
  • Place
    Habitat
    wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • river or stream floodplains
    • shores of rivers or lakes
  • Stem, shoot, branch
    Plant height
    2–25 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
    0.3–1 mm

Wetland Status

Occurs only in wetlands. (Wetland indicator code: OBL)

New England Distribution and Conservation Status

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
absent
Vermont
present

Conservation Status

Exact status definitions can vary from state to state. For details, please check with your state.

Connecticut
unrankable (S-rank: SU)
Massachusetts
extremely rare (S-rank: S1), endangered (code: E)
New Hampshire
extremely rare (S-rank: S1), endangered (code: E)
Vermont
extremely rare (S-rank: S1)

Native to North America?

Yes

Sometimes Confused With

Eleocharis aestuum:
floral scales rounded and unkeeled at the apex and tubercles 0.2-0.3 mm tall (vs. E. diandra, with floral scales acute and keeled near the apex and tubercles 0.1-0.2 mm tall).

Family

Cyperaceae

Genus

Eleocharis

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Information from Dichotomous Key of Flora Novae Angliae

5.  Eleocharis diandra C. Wright NC

Wright’s spikesedge. Eleocharis diandra C. Wright var. depressa Fern. • CT, MA, ME, NH, VT. Wet sand of major rivers and, rarely, lake shores. In New England known only from the Androscoggin, Connecticut, and Merrimack Rivers and Lake Champlain. This species has 
been frequently reported from fresh-tidal river shores (e.g., Seymour 1982, Gleason and Cronquist 1991). However, those reports are based on Eleocharis aestuum. Eleocharis diandra occurs in non-tidal situations, with the exception of its downstream populations on the Connecticut River in Hartford County, CT, where the river is minimally tidal.