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- Eleocharis quadrangulata
Eleocharis quadrangulata — square-stemmed spikesedge
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Facts
Square-stemmed spikesedge is broadly distributed east of the Mississippi River, but it is very rare in New England, with only a few populations inhabiting shallow water of lakes and slow moving rivers in Connecticut and Massachusetts.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams), shores of rivers or lakes
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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Characteristics
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- Stem shape in cross-section
- the stem is roughly quadrangular 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
- 1.8–3 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
- Fruit cross-section
- the fruit is biconvex or elliptic (widest in the middle and tapering to both ends) in cross-section
-
Flowers
- Anther color (dry)
- the anthers are orange to red-brown in color
- Anther length
- 2.3–2.9 mm
- Floral bristle color
- the bristles are pale brown to brown
- Floral bristle number
- 5-7
- Floral bristle relative length
-
- the bristles are between one tenth as long as the achene, and equal in length to the achene
- 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
- 4–6.2 mm
- Floral scale nerves
- 7 or more
- Floral scale shape
-
- the floral scales are obovate (roughly egg-shaped, but with the widest part above the middle)
- 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
- Stamen number
-
- 1
- 2
- 3
- Stigma number
-
- 2
- 3
- Style division
- the top two thirds of the style is divided
- floral bristle barbs
- the bristles have tiny barbs on them
- plantlets budding at flower bases
- no
-
Fruits or seeds
- Achene beak length
- 0 mm
- Achene surface texture
- the achene has stripes or ridges that run from end to end
- Achene tubercle relative width
- the tubercle is one half or less as wide as the achene
- Achene tubercle width
- 0.4–1 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
- 1.8–3 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
- 0.7–1.5 mm
-
Growth form
- Lifespan
- the plant lives more than two years
- Rhizome thickness
- 1.5–4 mm
- 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
- 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 fully-developed leaves with leaf blades on the main stem
- 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
- 3–6 mm
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
- shores of rivers or lakes
-
Stem, shoot, branch
- Plant height
- 30–105 cm
- Stem shape in cross-section
- the stem is roughly quadrangular in cross-section
- Stem texture near tip
- the stem feels smooth near the tip
- Stem thickness at midpoint
- 1–5.4 mm
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- extremely rare (S-rank: S1)
- Massachusetts
- historical (S-rank: SH)
var. crassior
- Connecticut
- extremely rare (S-rank: S1), endangered (code: E)
From Flora Novae Angliae dichotomous key
20. Eleocharis quadrangulata (Michx.) Roemer & J.A. Schultes NC
square-stemmed spikesedge. Eleocharis quadrangulata (Michx.) Roemer & J.A. Schultes var. crassior Fern.; Scirpus quadrangulatus Michx. • CT, MA. Shallow water of lakes and slow-moving rivers.
Native to North America?
Yes
Sometimes confused with
- Eleocharis equisetoides:
- reproductive stems +/- circular in cross-section, with transverse septa (vs. E. quadrangulata, with reproductive stems +/- square in cross-section, lacking transverse septa).
Synonyms
- Eleocharis quadrangulata (Michx.) Roemer & J.A. Schultes var. crassior Fern.
- Scirpus quadrangulatus Michx.