Utricularia radiata Small

floating 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

The upper leaves of floating bladderwort are inflated and help keep the inflorescence above the water surface. The bladders of bladderwort are not used for floatation but to catch insects for nutrients.

Habitat

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

Characteristics

Habitat
aquatic
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
  • the leaves are all submerged underwater
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
10–55 mm
Petal or sepal number
  • there are five petals, sepals, or tepals in the flower
  • there are two petals, sepals, or tepals in the flower
Petal color
yellow
Specific leaf type
the leaf is divided into two equal parts, with five or more levels of division
Floating leaf shape
the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
Fruit type (general)
the fruit is dry and splits open when ripe
Underwater leaf length
10–40 mm
Show All Characteristics
  • Flowers
    Anther color
    there is a noticeable pink, reddish or purplish tint to the anthers
    Carpels fused
    the carpels are fused to one another
    Flower lower lip length
    8–10 mm
    Flower number
    1–7
    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 type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Length of flower stalk
    10–20 mm
    Length of peduncle
    30–100 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
    15 mm
    Petal number
    2–5
    Petal or sepal number
    • there are five petals, sepals, or tepals in the flower
    • there are two petals, sepals, or tepals in the flower
    Pistil number
    1
    Sepal appearance
    the sepals resemble leaves in color and texture
    Sepal length
    2.5–3.5 mm
    Sepal number
    2
    Sepals fused only to sepals
    the sepals are separate from one another
    Stamen number
    1 or 2
    Stamen position relative to petals
    the stamens are lined up with the sepals
    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
    Style number
    0–1
  • Fruits or seeds
    Fruit type (general)
    the fruit is dry and splits 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
    • the plant lives only a single year or less
    Root septa
    the roots do not have transverse septa
    Roots floating in water
    there are no clusters of roots floating in the water
    Underground organs
    NA
  • 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 length
    20–55 mm
    Floating leaf shape
    the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    Floating leaf tip
    • the tip of the floating leaf blade is obtuse (bluntly pointed)
    • the tip of the floating leaf blade is rounded, with no point
    Floral bract form
    the bracts are much more lobed, or much less lobed, than the foliage leaves
    Floral bract length
    2–3 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
    10–55 mm
    Leaf blade veins
    the lateral veins radiate from the base and continue to spread away from the centerline of the leaf, or branch off the central vein at intervals
    Leaf position
    • some of the leaves are floating at the surface of the water
    • the leaves are all submerged underwater
    Leaf special features
    • the leaves have bladder-like traps
    • the leaves have inflated petioles or blades that help them float
    Leaf-like branch segments
    0
    Leaf-like branch shape
    the leaf-like branches are round
    Specific leaf type
    the leaf is divided into two equal parts, with five or more levels of division
    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
    Underwater leaf air passage number
    At least 1439
    Underwater leaf air passage relative width
    At least 4336
    Underwater leaf air passage row number
    0
    Underwater leaf blade edges
    the underwater leaf has smooth edges, without teeth
    Underwater leaf blade shape
    • NA
    • the underwater leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    • the underwater leaf blade is reniform (kidney-shaped; wider than long)
    • the underwater leaf blade is triangular, with the stalk or attachment point on one of the sides
    Underwater leaf blade veins
    1–3
    Underwater leaf length
    10–40 mm
    Underwater leaf stalk
    yes
    Underwater leaf tip shape
    • the tip of the underwater leaf is obtuse (bluntly pointed)
    • the tip of the underwater leaf is rounded, with no point
  • Place
    Habitat
    aquatic
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • 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)

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
unranked (S-rank: SNR)
New Hampshire
uncommon (S-rank: S3), W (code: W)
Vermont
extremely rare (S-rank: S1)

Native to North America?

Yes

Sometimes Confused With

Utricularia inflata:
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 (vs. U. radiata, with 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).

Synonyms

  • Utricularia inflata var. minor Chapman
  • Utricularia inflata var. radiata (Small) Stone

Genus

Utricularia

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Information from Dichotomous Key of Flora Novae Angliae

8.  Utricularia radiata Small N

Floating bladderwort. Utricularia inflata Walt. var. minor Chapman; U. inflata Walt. var. 
 radiata (Small) Stone • CT, MA, ME, NH, RI, VT; limited in VT to the southeastern portion of the state. Shallow water of lakes and ponds, infrequently associated with still sections of 
streams and inlets.