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• Lentibulariaceae
• Utricularia
• Utricularia inflata

Utricularia inflata — swollen bladderwort

Facts

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

• 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

From the dichotomous key of Flora Novae Angliae