Sparganium natans — arctic bur-reed
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Facts
Arctic bur-reed is found in shallow, still or slow-moving water, including pools in peatlands. The bur-reeds can only be confidently identified when they are in flower, and they typically flower sparsely and sporadically. Arctic bur-reed is protected in some New England states.
Habitat
Bogs, fens (calcium-rich wetlands), 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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enlargeCharacteristics
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade shape
- the leaf blade is linear (very narrow with more or less parallel sides)
- Leaf blade length
- 40–600 mm
- Flower petal color
-
- green to brown
- white
- Petal fusion
- the perianth parts are separate
- Inflorescence type
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Ovary position
- the ovary is above the point of petal and/or sepal attachment
- Fruit type (specific)
-
- the fruit is a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
- the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
- Fruit length
- 2–4 mm
-
Clonal plantlets
- Axillary bulblets
- there are no bulblets being produced in axils
-
Flowers
- Anther attachment
- the anther is attached by its base to the filament
- Bulblets replace flowers
- there are no bulblets where the flowers are located
- Carpels fused
- the carpel is solitary or (if 2 or more) the carpels are not fused to one another
- Flower petal color
-
- green to brown
- white
- Flower symmetry
- there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
- Fringed petal edges
- the petals are not fringed
- Hairs on flower stalk
- NA
- Inflorescence type
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Inflorescence width
- 5–12 mm
- Marks on petals
- there are no noticeable marks on the petals
- Nectar spur
- the flower has no nectar spurs
- Number of pistils
- 1
- Number of styles
- 1
- Ovary position
- the ovary is above the point of petal and/or sepal attachment
- Petal appearance
- the petals are green and/or leafy in texture
- Petal fusion
- the perianth parts are separate
- Sepal appearance
- the sepals resemble leaves in color and texture
- Sepals fused only to sepals
- the sepals are separate from one another
- Spathe
- the plant does not have a spathe
- Spathe form
- NA
- Stamen number
-
- 1 or 2
- 3
- 4
- 5
- 6
- 7
- 8
- Stamen position relative to petals
- NA
- Stamens fused
- the stamens are fused to one another at or near their bases
- Stamens fused outwards
- the stamens are not fused to the petals or tepals
- Style petal-like
- the style is not broad and flattened like a petal
- Tepals
- the petals and sepals are similar in size and color
-
Fruits or seeds
- Berry color
- NA
- Capsule ridges
- NA
- Fruit beak length
- 0.5–1.5 mm
- Fruit compartments
- there is only one locule in the fruit
- Fruit length
- 2–4 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Fruit type (specific)
-
- the fruit is a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
- the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
- Fruit width
- 1–1.5 mm
- Other markings on berry
- NA
-
Glands or sap
- Sap
- the sap is clear and watery
-
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
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade basal lobes
- the leaf blades do not have basal lobes
- Leaf blade base
- the leaf has no stalk
- Leaf blade base shape
- the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
- Leaf blade cross-section
-
- the leaf blade is U- or V-shaped
- the leaf blade is more or less flat in cross-section
- Leaf blade faces
- both surfaces of the leaf blade are exposed
- Leaf blade form
- Fully-formed (i.e., expanded), +/- green leaf blades are found somewhere on the plant
- Leaf blade length
- 40–600 mm
- Leaf blade shape
- the leaf blade is linear (very narrow with more or less parallel sides)
- Leaf blade surface colors
- the upper side of the leaf blade is relatively uniform in color
- Leaf blade veins
- the lateral veins are parallel or slightly arched in the direction of the tip
- Leaf type
- the leaves are simple (lobed or unlobed but not separated into leaflets
- Stipule twining
- NA
- Stipules
- there are no stipules on this plant
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Specific habitat
-
- bogs
- fens (calcium-rich wetlands)
- in lakes or ponds
- in rivers or streams
- shores of rivers or lakes
-
Scent
- Plant odor
- the leaves have no particular smell
-
Stem, shoot, branch
- Flowering stem leaves
- there is at least one fully-formed leaf on the flowering stem
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
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- extremely rare (S-rank: S1), endangered (code: E)
- Massachusetts
- extremely rare (S-rank: S1), endangered (code: E)
- New Hampshire
- rare (S-rank: S2), threatened (code: T)
- Vermont
- rare (S-rank: S2), threatened (code: T)
From Flora Novae Angliae dichotomous key
7. Sparganium natans L. NC
arctic bur-reed. Sparganium minimum (Hartman) Wallr. • CT, MA, ME, NH, VT. Shorelines, pools in peatlands, and shallow, acidic to basic, still or slow-moving water.