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Heteranthera dubia — grass-leaved mud-plantain

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Facts

Grass-leaved mud-plantain is found in neutral or basic, slow-moving water of lakes and rivers. The shape of the leaf blades is variable, being somewhat shorter and wider if the plant is subjected to a current, longer and narrower in plants growing in ponds or lakes.

Habitat

Lacustrine (in lakes or ponds), riverine (in rivers or streams)

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
aquatic
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
Leaf position
  • some of the leaves are floating at the surface of the water
  • the leaves are all submerged underwater
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade length
20–100 mm
Petal or sepal number
there are six petals, sepals, or tepals in the flower
Petal color
yellow
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
1–5 mm
Fruit type (general)
the fruit is dry but does not split open when ripe
Underwater leaf length
30–100 mm
Show all characteristics

  • Clonal plantlets

    Turion length
    0 mm

  • Flowers

    Anther color
    there is a noticeable pink, reddish or purplish tint to the anthers
    Anther length
    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
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    Inflorescence type
    the inflorescence has only one flower on it
    Length of flower stalk
    0 mm
    Length of peduncle
    0 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    3
    Ovary position
    the sepals and/or petals are attached below the ovary
    Palate on corolla
    no
    Petal and sepal arrangement
    the flower includes only one cycle of petals or sepals
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal color
    yellow
    Petal fringed edges
    the petals are not fringed
    Petal fusion
    • the perianth parts are fused to form a tube, cup, or bell shape
    • the perianth parts are separate
    Petal hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    4–11 mm
    Petal number
    3
    Petal or sepal number
    there are six petals, sepals, or tepals in the flower
    Pistil number
    1
    Sepal appearance
    the sepals resemble petals in color and texture
    Sepal length
    4–11 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 length
    2–10 mm
    Stamen number
    3
    Stamen position relative to petals
    NA
    Stamens fused
    the stamens are not fused to one another
    Stamens fused to petals
    the stamens are fused near the bases of the petals or tepals
    Style number
    1

  • Fruits or seeds

    Fruit length
    10 mm
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    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)

  • 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
    • the plant has a rhizome (a horizontal underground stem with roots growing from it)
    • there are only slender roots on the plant

  • Leaves

    Bract position (Sparganium)
    NA
    Floating leaf basal lobes
    NA
    Floating leaf blade width
    1–3 mm
    Floating leaf length
    20–40 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 obtuse (bluntly pointed)
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade length
    20–100 mm
    Leaf blade veins
    the lateral veins are parallel or slightly arched in the direction of the tip
    Leaf blade width
    1–5 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
    1–5 mm
    Underwater leaf length
    30–100 mm
    Underwater leaf stalk
    no
    Underwater leaf stalk length
    0 mm
    Underwater leaf tip shape
    the tip of the underwater leaf is obtuse (bluntly pointed)
    Veins in floating leaf
    0

  • Place

    Habitat
    aquatic
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • in lakes or ponds
    • in rivers or streams

  • 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
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.

Maine
uncommon (S-rank: S3), special concern (code: SC)
Massachusetts
rare to uncommon (S-rank: S2S3)
New Hampshire
rare (S-rank: S2), threatened (code: T)
Vermont
fairly widespread (S-rank: S4)

From Flora Novae Angliae dichotomous key

1.  Heteranthera dubia (Jacq.) MacM. N

grass-leaved mud-plantain. Commelina dubia Jacq.; Heteranthera graminea (Michx.) Vahl; Zosterella dubia (Jacq.) Small • CT, MA, ME, NH, VT. Shallow, still or slow-moving, circumneutral to basic water of lakes and rivers. This vegetatively plastic species has been considered to belong to a different genus ( Zosterella) based on convincing morphological characters. However, phylogenetic work has shown it to be nested within Heteranthera (see Horn 2002 for discussion and additional references).

Native to North America?

Yes

Sometimes confused with

Sparganium angustifolium:
leaves thicker, nearly opaque, flat to planoconvex, and perianth white to green, inconspicuous (vs. H. dubia, with leaves thin, translucent, flat, and perianth yellow, conspicuous).

Synonyms

  • Commelina dubia Jacq.
  • Heteranthera graminea (Michx.) Vahl
  • Zosterella dubia (Jacq.) Small

Family

Pontederiaceae

Genus

Heteranthera