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- Elodea nuttallii
Elodea nuttallii — free-flowered waterweed
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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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Facts
Free-flowered waterweed is a native aquatic plant that is an invasive weed in Europe. It is named after Thomas Nuttall (1786-1859), a highly influential field botanist who collected widely across America, especially in the West.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
Characteristics
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf position
- the leaves are all submerged underwater
- Leaf arrangement
- whorled: there are three or more leaves per node along the stem
- Leaf blade length
- 4–15.5 mm
- Petal or sepal number
- there are three petals, sepals, or tepals in the flower
- Petal color
- white
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Floating leaf shape
- NA
- Underwater leaf blade width
- 0.9–2.4 mm
- Fruit type (general)
- the fruit is fleshy
- Underwater leaf length
- 4–15.5 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther color
- there is a noticeable pink, reddish or purplish tint to the anthers
- Anther length
- 1–1.4 mm
- Carpels fused
- the carpels are fused to one another
- Flower lower lip length
- 0 mm
- Flower number
- 1
- Flower position
-
- the flowers are above the surface of the water
- the flowers are floating on the surface of the water
- Flower symmetry
- there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
- Inflorescence type
-
- the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
- the inflorescence has only one flower on it
- Length of flower stalk
- Up to 90 mm
- Nectar spur
- the flower has no nectar spurs
- Ovary position
-
- NA
- the sepals and/or petals are attached above the ovary
- Palate on corolla
- no
- Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
- Petal color
- white
- Petal fringed edges
- the petals are not fringed
- Petal fusion
- the perianth parts are separate
- Petal length
- 1–2.5 mm
- Petal number
- 3
- Petal or sepal number
- there are three petals, sepals, or tepals in the flower
- Pistil number
-
- 0
- 1
- Sepal length
- Up to 2 mm
- Sepal number
- 3
- Sepals fused only to sepals
-
- the sepals are fused to each other (not other flower parts), at least near their bases
- the sepals are separate from one another
- Spur length
- 0 mm
- Stamen number
- 9
- Stamen position relative to petals
- NA
- Stamens fused
-
- the stamens are fused to one another at or near their bases
- the stamens are not fused to one another
- Stamens fused to petals
- the stamens are not fused to the petals or tepals
- Style length
- 1.2–2 mm
- Style number
- 3
-
Fruits or seeds
- Fruit length
- 5–7 mm
- Fruit type (general)
- the fruit is fleshy
- Fruit type (specific)
- the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)
- Fruit width
- 1.5–2 mm
-
Glands or sap
- Oil glands on nodes
- none of the nodes have oil glands
- Sap
- the sap is clear and watery
-
Growth form
- Lifespan
- the plant lives more than two years
- Root septa
- the roots do not have transverse septa
- Roots floating in water
- there are no clusters of roots floating in the water
- Turions
- there are no turions on the plant
- Underground organs
- there are only slender roots on the plant
-
Leaves
- Bract position (Sparganium)
- NA
- Bracts
- the flowers or their pedicels have bracts at their bases
- Floating leaf basal lobes
- NA
- Floating leaf blade width
- 0 mm
- Floating leaf length
- 0 mm
- Floating leaf shape
- NA
- Floating leaf tip
- NA
- Floral bract form
- the bracts are roughly as lobed as the foliage leaves
- Floral bract length
- 2.2–15 mm
- Leaf arrangement
- whorled: there are three or more leaves per node along the stem
- Leaf blade length
- 4–15.5 mm
- Leaf blade veins
- the lateral veins radiate from the base and continue to spread away from the centerline of the leaf, or branch off the central vein at intervals
- Leaf blade width
- 0.9–2.4 mm
- Leaf position
- the leaves are all submerged underwater
- Leaf special features
- none of the mentioned special features are present
- Leaf-like branch segments
- 0
- Leaf-like branch shape
- NA
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Staminate bract edge (Myriophyllum)
- NA
- Stipule appearance
- the stipules are delicate and translucent
- Stipules
- the plant has stipules
- Trap-bladder length
- 0 mm
- Underwater leaf air passage number
- At least 1439
- Underwater leaf air passage relative width
- At least 4336
- Underwater leaf air passage row number
- 0
- Underwater leaf blade edges
- the underwater leaf blade edges are toothed
- Underwater leaf blade shape
-
- the underwater leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the underwater leaf blade is linear (very narrow with more or less parallel sides)
- Underwater leaf blade veins
- 1
- Underwater leaf blade width
- 0.9–2.4 mm
- Underwater leaf length
- 4–15.5 mm
- Underwater leaf stalk
- no
- Underwater leaf stalk length
- 0 mm
- Underwater leaf tip shape
- the tip of the underwater leaf is acute (sharply pointed)
- Veins in floating leaf
- 0
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
-
Stem, shoot, branch
- Flowering stem growth form
-
- the flowering stem is upright
- the flowering stem trails along the substrate, or floats in the water
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
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- unranked (S-rank: SNR)
- Vermont
- uncommon (S-rank: S3)
Native to North America?
Yes
Sometimes confused with
Synonyms
- Anacharis nuttallii Planch.
Family
Genus
From the dichotomous key of Flora Novae Angliae
2. Elodea nuttallii (Planch.) St. John N
free-flowered waterweed. Anacharis nuttallii Planch. • CT, MA, ME, NH, RI, VT. Shallow, still or slow-moving, slightly acidic to basic waters of lakes and rivers.