Eleocharis flavescens — yellow spikesedge
![Plant form: Eleocharis flavescens. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/eleocharis-flavescens-olivacea-ha-ahaines-b.jpg)
![Flowers and fruits: Eleocharis flavescens. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/eleocharis-flavescens-olivacea-ff-ahaines-a.jpg)
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Facts
Yellow spikesedge is a common plant of shorelines, marshes, river shores and peat swamps, found in all New England states. It is called "yellow" spikesedge for its straw-colored achenes. These have long bristles, which give the whole spike a "curly" appearance. It propagates vegeatatively on skinny rhizomes.
Habitat
Bogs, brackish or salt marshes and flats, floodplain (river or stream floodplains), marshes, shores of rivers or lakes, wetland margins (edges of wetlands)
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.
enlargeCharacteristics
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- 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
- 0.5–1.1 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 triangular to terete (circular) in cross-section
-
Flowers
- Anther length
- 0.7–1 mm
- Floral bristle color
- the bristles are white
- Floral bristle number
-
- 0
- 1-4
- 5-7
- 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
- 1–3 mm
- Floral scale nerves
- 0
- Floral scale shape
- the floral scales are elliptic (widest in the middle and tapering toward each end)
- 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
-
- 1
- 2
- 3
- Stigma number
- 2
- 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
- yes
-
Fruits or seeds
- Achene beak length
- 0 mm
- Achene surface texture
- the achene has very tiny pits or depressions on it
- Achene tubercle relative width
- the tubercle is one half or less as wide as the achene
- Achene tubercle width
- 0.2–0.4 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 triangular to terete (circular) in cross-section
- Fruit length
- 0.5–1.1 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
- 0.3–0.7 mm
-
Growth form
- Lifespan
- the plant lives more than two years
- Rhizome thickness
- 0.5–1 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 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
- 1–2 mm
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- bogs
- brackish or salt marshes and flats
- edges of wetlands
- marshes
- river or stream floodplains
- shores of rivers or lakes
-
Stem, shoot, branch
- Plant height
- 3–28 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
- 0.3–0.6 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.
var. olivacea
- Massachusetts
- widespread (S-rank: S5)
- Vermont
- extremely rare (S-rank: S1)
Subspecies and varieties
Our variety is Eleocharis flavescens (Poir.) Urban var. olivacea (Torr.) Gleason.
From Flora Novae Angliae dichotomous key
11. Eleocharis flavescens (Poir.) Urban var. olivacea (Torr.) Gleason N
yellow spikesedge. Eleocharis olivacea Torr. • CT, MA, ME, NH, RI, VT. Shorelines, marshes, tidal river shores, peatlands.
Native to North America?
Yes
Sometimes confused with
- Eleocharis intermedia:
- styles trifid, achenes compressed-trigonous, and leaf sheaths variable at apex, but without a prolonged white, scarious apex (vs. E. flavescens, with styles usually bifid, achenes biconvex, and leaf sheaths prolonged at summit into a white, scarious tip).
Synonyms
- Eleocharis olivacea Torr.