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- Alisma gramineum
Alisma gramineum — narrow-leaved water-plantain
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Facts
Narrow-leaved water-plantain is found across Europe and Asia, as well as North America. In North America it is distributed from California to Wisconsin, and disjunct around the eastern Great Lakes to northwestern Vermont. In our region it is found mainly in Vermont's Lake Champlain and its tributaries, in shallow water or along muddy shores.
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
- Vermont
- Leaf position
-
- some of the leaves are floating at the surface of the water
- the leaves are all submerged underwater
- Leaf arrangement
- basal: the leaves are growing only at the base of the plant
- Leaf blade length
- 20–1000 mm
- Petal or sepal number
- there are three petals, sepals, or tepals in the flower
- Petal color
-
- purple
- white
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Floating leaf shape
- the leaf blade is linear (very narrow with more or less parallel sides)
- Underwater leaf blade width
- 2–30 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Underwater leaf length
- 150–1000 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther color
- there is a noticeable pink, reddish or purplish tint to the anthers
- Anther length
- 0.3–0.6 mm
- Carpels fused
- the carpel is solitary or (if 2 or more) the carpels are not fused to one another
- Flower lower lip length
- 0 mm
- Flower position
-
- the flowers are above the surface of the water
- the flowers are below the surface of the water
- Flower symmetry
- there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
- Inflorescence length
- Up to 500 mm
- Inflorescence type
- the inflorescence is a panicle (branched, with the individual flowers on stalks)
- Length of flower stalk
- 5–40 mm
- Nectar spur
- the flower has no nectar spurs
- Number of carpels
- At least 3
- Ovary position
- the sepals and/or petals are attached below the ovary
- Palate on corolla
- no
- Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
- Petal appearance
- the petals are thin and delicate, and pigmented (colored other than green or brown)
- Petal color
-
- purple
- white
- Petal fringed edges
-
- the petals are fringed
- the petals are not fringed
- Petal fusion
- the perianth parts are separate
- Petal hairs on inner/upper surface
- there are no hairs on the inner/upper petal surface
- Petal length
- 2–4 mm
- Petal number
- 3
- Petal or sepal number
- there are three petals, sepals, or tepals in the flower
- Pistil number
- 6 or more
- Sepal appearance
- the sepals resemble leaves in color and texture
- Sepal length
- 1.5–3 mm
- Sepal number
- 3
- Spur length
- 0 mm
- Stamen number
- 6
- Stamen position relative to petals
- NA
- Stamens fused
- the stamens are not fused to one another
- Stamens fused to petals
- the stamens are not fused to the petals or tepals
- Style length
- 0.4–0.5 mm
- Style number
- 15–20
-
Fruits or seeds
- Fruit length
- 2–2.7 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Fruit type (specific)
- the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
-
Glands or sap
- Oil glands on nodes
- none of the nodes have oil glands
- Sap
- the sap is milky and opaque, and may be white or colored
-
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
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
-
Leaves
- Bract position (Sparganium)
- NA
- Bract relative length
- At least 1379 mm
- Bracts
- the flowers or their pedicels have bracts at their bases
- Floating leaf basal lobes
-
- NA
- no
- Floating leaf blade width
- 2–30 mm
- Floating leaf length
- 0 mm
- Floating leaf shape
- the leaf blade is linear (very narrow with more or less parallel sides)
- Floating leaf tip
-
- the tip of the floating leaf blade is acute (sharply pointed)
- the tip of the floating leaf blade is obtuse (bluntly pointed)
- Floral bract form
- the bracts are roughly as lobed as the foliage leaves
- Leaf arrangement
- basal: the leaves are growing only at the base of the plant
- Leaf blade length
- 20–1000 mm
- Leaf blade veins
- the lateral veins are parallel or slightly arched in the direction of the tip
- Leaf blade width
- 2–30 mm
- Leaf position
-
- some of the leaves are floating at the surface of the water
- 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
- NA
- Stipule fused to leaf
- NA
- Stipules
- there are no stipules on the plant
- Stipules fused around stem
- NA
- Trap-bladder length
- 0 mm
- Underwater leaf blade edges
- the underwater leaf has smooth edges, without teeth
- Underwater leaf blade shape
- the underwater leaf blade is linear (very narrow with more or less parallel sides)
- Underwater leaf blade width
- 2–30 mm
- Underwater leaf length
- 150–1000 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)
- the tip of the underwater leaf is obtuse (bluntly pointed)
- Veins in floating leaf
- 0
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
- shores of rivers or lakes
-
Stem, shoot, branch
- Flowering stem growth form
- the flowering stem is upright
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
In New England
Distribution
- Connecticut
- absent
- Maine
- absent
- Massachusetts
- absent
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- present
Conservation status
None
From Flora Novae Angliae dichotomous key
1. Alisma gramineum Lej. N
narrow-leaved water-plantain. Alisma gramineum Lej. var. angustissimum (DC.) Hendricks • VT; primarily Lake Champlain and its tributaries. Circumneutral still or slow-moving water.
Native to North America?
Yes
Sometimes confused with
- Helanthium tenellum:
- flowers with around 9 stamens and multiple whorls of carpels, collectively arranged in an umbel (vs. A. gramineum, with flowers with 6 stamens and single whorl of carpels, collectively arranged in a panicle).
Synonyms
- Alisma gramineum Lej. var. angustissimum (DC.) Hendricks