Utricularia inflata Walt.

swollen bladderwort

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Swollen bladderwort is native to southern and eastern North America, but it has been introduced in Massachusetts, as well as New York and the state of Washington. This species can be quite invasive, becoming dominant in ponds and displacing other native aquatic plants. It may be expected to continue expanding its range.

Habitat

Lacustrine (in lakes or ponds)

Characteristics

Habitat
  • aquatic
  • wetlands
New England state
Massachusetts
Leaf position
some of the leaves are floating at the surface of the water
Leaf arrangement
  • alternate: there is one leaf per node along the stem
  • whorled: there are three or more leaves per node along the stem
Leaf blade length
20–100 mm
Petal or sepal number
there are five petals, sepals, or tepals in the flower
Petal color
yellow
Specific leaf type
  • the leaf has three or more lobes distributed along a central axis
  • the leaf is divided into two equal parts, with five or more levels of division
  • the leaf is pinnately compound (i.e., it has three or leaflets distributed along a central axis
Floating leaf shape
  • the leaf blade is linear (very narrow with more or less parallel sides)
  • the leaf blade is oblong (rectangular but with rounded ends)
Fruit type (general)
the fruit is dry and splits open when ripe
Underwater leaf length
2–10 mm
Show All Characteristics
  • Flowers
    Carpels fused
    the carpels are fused to one another
    Chasmogamous flowers
    absent
    Flower lower lip length
    20–25 mm
    Flower number
    4–17
    Flower position
    the flowers are above the surface of the water
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Inflorescence length
    20–50 mm
    Inflorescence type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Length of flower stalk
    10–35 mm
    Length of peduncle
    10–30 mm
    Nectar spur
    the flower has nectar spurs
    Number of carpels
    2
    Ovary position
    the sepals and/or petals are attached below the ovary
    Palate on corolla
    yes
    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
    yellow
    Petal fringed edges
    the petals are not fringed
    Petal fusion
    the perianth parts are fused to form a tube, cup, or bell shape
    Petal hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    20–25 mm
    Petal number
    5
    Petal or sepal number
    there are five petals, sepals, or tepals in the flower
    Pistil number
    1
    Sepal appearance
    the sepals resemble leaves in color and texture
    Sepal length
    3–5 mm
    Sepal number
    2
    Sepals fused only to sepals
    the sepals are fused to each other (not other flower parts), at least near their bases
    Stamen number
    1 or 2
    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 length
    At least 0 mm
  • Fruits or seeds
    Embryo coiling (Potamogeton)
    NA
    Fruit length
    3–6 mm
    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a pyxis (when dry it splits around the middle, and the top falls off, exposing the seeds)
    Fruit width
    3–6 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
    NA
    Roots floating in water
    there are no clusters of roots floating in the water
    Underground organs
    NA
  • Leaves
    Bract position (Sparganium)
    NA
    Bracts
    the flowers or their pedicels have bracts at their bases
    Floating leaf basal lobes
    no
    Floating leaf length
    30–80 mm
    Floating leaf shape
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • the leaf blade is oblong (rectangular but with rounded ends)
    Floral bract form
    the bracts are much more lobed, or much less lobed, than the foliage leaves
    Floral bract length
    3–7 mm
    Leaf arrangement
    • alternate: there is one leaf per node along the stem
    • whorled: there are three or more leaves per node along the stem
    Leaf blade length
    20–100 mm
    Leaf position
    some of the leaves are floating at the surface of the water
    Leaf special features
    • the leaves have bladder-like traps
    • the leaves have inflated petioles or blades that help them float
    Leaf-like branch shape
    the leaf-like branches are round
    Specific leaf type
    • the leaf has three or more lobes distributed along a central axis
    • the leaf is divided into two equal parts, with five or more levels of division
    • the leaf is pinnately compound (i.e., it has three or leaflets distributed along a central axis
    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
    1–3 mm
    Underwater leaf blade edges
    the underwater leaf has tiny, one-celled spines or points along the edge
    Underwater leaf blade shape
    • NA
    • the underwater leaf blade is obovate (egg-shaped, but with the widest point above the middle of the underwater leaf blade)
    • the underwater leaf blade is orbicular (roughly circular, as wide as long)
    • the underwater leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    Underwater leaf length
    2–10 mm
    Underwater leaf stalk
    no
    Underwater leaf tip shape
    the tip of the underwater leaf is truncate (ends abruptly in a more or less straight line as though cut off)
  • Place
    Habitat
    • aquatic
    • wetlands
    New England state
    Massachusetts
    Specific habitat
    in lakes or ponds
  • Stem, shoot, branch
    Flowering stem growth form
    the flowering stem trails along the substrate, or floats in the water

Wetland Status

Not classified

New England Distribution and Conservation Status

Distribution

Connecticut
present
Maine
absent
Massachusetts
present
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation Status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
not applicable (S-rank: SNA)

Native to North America?

Yes and no (some introduced)

Sometimes Confused With

Utricularia radiata:
raceme with mostly 1-5 flowers, peduncle above the inflated branches 3-10 cm long, inflated branches 10-40 mm long bearing branches only near the apex, and sepals 2.5-3.5 mm long (vs. Utricularia inflata, with raceme with mostly 9–14 flowers, peduncle above the inflated branches 10-30 cm, inflated branches 30-80 mm long bearing branches in the distal half, and sepals 3-5 mm long).

Synonyms

  • Plectoma inflata (Walt.) Raf.
  • Utricularia ceratophylla Michx.

Genus

Utricularia

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Information from Dichotomous Key of Flora Novae Angliae

4.  Utricularia inflata Walt. E

swollen bladderwort. Plectoma inflata (Walt.) Raf.; Utricularia ceratophylla Michx. • MA. Shallow water of ponds.