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- Dichotomous Key
- Alismataceae
- Alisma
- Alisma subcordatum
Alisma subcordatum — southern water-plantain
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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.
Found this plant? Take a photo and post a sighting.
Facts
Southern water-plantain is found in marshes, ditches, and shallow lakes and streams. The Cherokee used it to make a topical aid for sores, wounds, bruises, swelling, and ulcers, and the Cree took the stem base internally to treat stomach and bowel conditions.
Habitat
Anthropogenic (man-made or disturbed habitats), lacustrine (in lakes or ponds), marshes, riverine (in rivers or streams), shores of rivers or lakes, wetland margins (edges of wetlands)
Characteristics
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf position
- some of the leaves are floating at the surface of the water
- Leaf arrangement
- basal: the leaves are growing only at the base of the plant
- Leaf blade length
- Up to 150 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
-
- the leaf blade is elliptic (widest near the middle and tapering at both ends)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- Underwater leaf blade width
- 0 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Underwater leaf length
- 0 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther color
- there is a noticeable pink, reddish or purplish tint to the anthers
- Anther length
- 0.4–0.6 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 1000 mm
- Inflorescence type
- the inflorescence is a panicle (branched, with the individual flowers on stalks)
- Length of peduncle
- Up to 600 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
- white
- Petal fringed edges
-
- the petals are fringed
- the petals are not fringed
- Petal hairs on inner/upper surface
- there are no hairs on the inner/upper petal surface
- Petal length
- 1.8–2.5 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
- 1.5–6 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
- 0.2–0.4 mm
- Style number
- 15–20
-
Fruits or seeds
- Fruit length
- 1.5–2.2 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
- no
- Floating leaf blade width
- 20–120 mm
- Floating leaf length
- 0 mm
- Floating leaf shape
-
- the leaf blade is elliptic (widest near the middle and tapering at both ends)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- 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
- Floral bract length
- Up to 10 mm
- Leaf arrangement
- basal: the leaves are growing only at the base of the plant
- Leaf blade length
- Up to 150 mm
- Leaf blade veins
- the lateral veins are parallel or slightly arched in the direction of the tip
- Leaf blade width
- 20–120 mm
- Leaf position
- some of the leaves are floating at the surface of the water
- 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
- NA
- Underwater leaf blade shape
- NA
- Underwater leaf blade veins
- 0
- Underwater leaf blade width
- 0 mm
- Underwater leaf length
- 0 mm
- Underwater leaf stalk
- NA
- Underwater leaf stalk length
- 0 mm
- Underwater leaf tip shape
- NA
- Veins in floating leaf
- 0
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- edges of wetlands
- in lakes or ponds
- in rivers or streams
- man-made or disturbed habitats
- marshes
- 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)
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
- widespread (S-rank: S5)
Native to North America?
Yes
Sometimes confused with
- Alisma triviale:
- petals conspicuously longer than the sepals and fruits 1.8-3 mm long (vs. A. subcordatum, with petals +/- as long as the sepals and fruits 1.5-2.2 mm long).
Synonyms
- Alisma plantago-aquatica L. ssp. subcordatum (Raf.) Hultén
- Alisma plantago-aquatica L. var. parviflorum (Pursh) Torr.
Family
Genus
From the dichotomous key of Flora Novae Angliae
2. Alisma subcordatum Raf. N
southern water-plantain. Alisma plantago-aquatica L. var. parviflorum (Pursh) Torr.; A. plantago-aquatica L. ssp. subcordatum (Raf.) Hultén • CT, MA, ME, NH, RI, VT. Marshes, muddy shorelines, ditches, and shallow, circumneutral to slightly basic water of lakes and slow-moving streams.