Eriophorum tenellum — few-nerved cottonsedge
![Plant form: Eriophorum tenellum. ~ By William and Linda Steere and the C.V. Starr Virtual Herbarium. ~ Copyright © 2024 William and Linda Steere and the C.V. Starr Virtual Herbarium. ~ Barbara Thiers, Director; bthiers[at]nybg.org ~ C.V. Starr Herbarium - NY Botanical Gardens](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/eriophorum-tenellum-ha-cvstarr1.jpg)
![Inflorescences: Eriophorum tenellum. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/eriophorum-tenellum-in-ahaines.jpg)
Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.
Facts
Few-nerved cottonsedge inhabits bogs, fens and meadows in all New England states. This handsome cottonsedge bears large tufts of spikelets that are white and wool-like when mature ("eriophorum" derives from the Greek word for "wool-bearing"). The common name, "few-nerved" doesn't refer to this plant's cool-headedness; rather to the absence of nerves or ribs on the red-brown floral scales.
Habitat
Bogs, fens, meadows and fields
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
- 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
- 1–3 mm
- Leaf blade cross-section
-
- the leaf blade is flat or rolled in at the edges
- the leaf blade is triangular in cross-section
- Inflorescence position
- the inflorescence is at the tip of the plant
- Inflorescence branching
-
- the inflorescence is branched
- the inflorescence is on one or more stems with no branches
- Fruit type (general)
-
- the fruit is like a seed, and surrounded by hairs
- the fruit is like a seed, and surrounded by scales
- Fruit length
- 2.5–3 mm
- Leaf position on plant
- some leaf attachment points are above the midpoint of the stem
- Perianth composition
- there are bristles attached at the base of the achene
- Fruit cross-section
- the fruit is triangular to terete (circular) in cross-section
-
Flowers
- Anther length
- 1–2 mm
- Floral bristle color
- the bristles are white
- Floral bristle number
- 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
- 3–4.5 mm
- Floral scale nerves
-
- 1
- 2-5
- Floral scale shape
-
- the floral scales are elliptic (widest in the middle and tapering toward each end)
- the floral scales are ovate (roughly egg-shaped)
- Floral scale translucent
- the floral scales are opaque
- Inflorescence bract angle
- the bracts are vertical or angled only slightly outwards
- Inflorescence bract number
- there is just one bract on the inflorescence
- Inflorescence bract position (Sparganium)
- NA
- Inflorescence bracts
- there is only one bract, and it looks like a continuation of the stem
- Inflorescence branching
-
- the inflorescence is branched
- the inflorescence is on one or more stems with no branches
- Inflorescence crowding
- the inflorescence is at least somewhat spread out, with at least one branch coming from the main stem
- 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 are two or more flowers, spikes or flower clusters on a branched inflorescence
- 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
- 3
- Style division
- the top two thirds of the style is divided
- floral bristle barbs
- the bristles do not have barbs on them
-
Fruits or seeds
- Achene tubercle relative width
- NA
- Achene tubercle width
- 0 mm
- Capsule relative length
- NA
- Fruit cross-section
- the fruit is triangular to terete (circular) in cross-section
- Fruit length
- 2.5–3 mm
- Fruit type (general)
-
- the fruit is like a seed, and surrounded by hairs
- the fruit is like a seed, and surrounded by scales
- Fruit type (specific)
- the fruit is an achene (dry, seed-like fruit) without a tubercle (a swelling or projection, usually of a different color or texture)
- Locules in capsule
- NA
- Seed length
- 0 mm
- Seed tail relative length
- 0 mm
- Seed tails
- NA
- Tubercle height
- 0 mm
-
Growth form
- Lifespan
- the plant lives more than two years
- 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
-
- the leaf blade is flat or rolled in at the edges
- the leaf blade is triangular in cross-section
- Leaf blade length
- 30–250 mm
- Leaf blade width
- 1–3 mm
- Leaf form
- all the leaves hold their form out of water
- Leaf position on plant
- some leaf attachment points are above the midpoint of the stem
- Leaf septa
- the leaf blades do not have transverse septa
- Leaf sheath hairs
- the leaf sheathes are without hairs
- Pedicel length (Typha)
- 0 mm
- Stem leaf blade ligules
- the plant has ligules at the leaf blade bases
- Stem leaf blades
- there are fully-developed leaves with leaf blades on the main stem
-
Place
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- bogs
- fens
- meadows or fields
-
Stem, shoot, branch
- Plant height
- 10–90 cm
- Stem shape in cross-section
- the stem is round or oval in cross-section
- Stem texture near tip
- the edges of the stem feel rough near the tip
- Stem thickness at midpoint
- 0.5–1.5 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.
- Massachusetts
- widespread (S-rank: S5)
- Vermont
- extremely rare to rare (S-rank: S1S2)
From Flora Novae Angliae dichotomous key
3. Eriophorum tenellum Nutt. N
few-nerved cottonsedge. CT, MA, ME, NH, RI, VT. Bogs, fens, meadows.
Native to North America?
Yes
Sometimes confused with
- Eriophorum gracile:
- uppermost leaf blade 1–4 cm long, shorter than its sheath, and apical portion of stems and peduncles not scabrous (vs. E. tenellum, with the uppermost leaf blade 3–25 cm long, as long or longer than its associated sheath, and apical portion of stem and peduncles scabrous).