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Butomus umbellatus — flowering-rush

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Facts

Flowering-rush is an introduced aquatic plant from Eurasia that has become a serious invasive weed in the Great Lakes. It was first observed in the St. Lawrence River in 1897. In New England it is common only in the Lake Champlain Valley, and rare elsewhere.

Habitat

Marshes, shores of rivers or lakes

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
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • Vermont
Leaf position
  • some of the leaves are floating at the surface of the water
  • the leaves are all submerged underwater
Leaf arrangement
the leaves are growing only at the base of the plant (basal)
Leaf blade length
Up to 2700 mm
Petal or sepal number
there are three petals, sepals, or tepals in the flower
Petal color
pink
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
5–10 mm
Fruit type (general)
the fruit is dry and splits open when ripe
Underwater leaf length
Up to 2700 mm
Show all characteristics
  • Clonal plantlets

    Turion length
    0 mm
  • Flowers

    Anther color
    the anthers show no hint of a pink, reddish or purplish tint
    Anther length
    1 mm
    Carpels fused
    the carpels are fused to one another
    Flower lower lip length
    0 mm
    Flower number
    20–25
    Flower position
    the flowers are above the surface of the water
    Inflorescence type
    the inflorescence is an umbel (with an axis so short it appears the flowers all originate from the same point)
    Length of flower stalk
    40–100 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    6
    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
    pink
    Petal fringed edges
    • the petals are fringed
    • the petals are not fringed
    Petal fusion
    the perianth parts are separate
    Petal hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    10–15 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 petals in color and texture
    Sepal length
    10–15 mm
    Sepal number
    3
    Sepals fused only to sepals
    the sepals are separate from one another
    Spur length
    0 mm
    Stamen length
    4–5.5 mm
    Stamen number
    9
    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 number
    6
  • Fruits or seeds

    Fruit length
    10 mm
    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a follicle (has one ovary that splits along one side to release the 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)
  • 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
    5–10 mm
    Floating leaf length
    Up to 2700 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 acuminate (tapers to a long, thin point)
    • the tip of the floating leaf blade is acute (sharply pointed)
    Floral bract form
    the bracts are roughly as lobed as the foliage leaves
    Leaf arrangement
    the leaves are growing only at the base of the plant (basal)
    Leaf blade length
    Up to 2700 mm
    Leaf blade veins
    the lateral veins are parallel or slightly arched in the direction of the tip
    Leaf blade width
    5–10 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
    5–10 mm
    Underwater leaf length
    Up to 2700 mm
    Underwater leaf stalk
    no
    Underwater leaf stalk length
    0 mm
    Underwater leaf tip shape
    • the tip of the underwater leaf is acuminate (tapers to a long, thin point)
    • the tip of the underwater leaf is acute (sharply pointed)
  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • Vermont
    Specific habitat
    • 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)

In New England

Distribution

Connecticut
present, invasive, prohibited
Maine
present
Massachusetts
present
New Hampshire
absent
Rhode Island
absent
Vermont
present, invasive, prohibited

Conservation status

None

From Flora Novae Angliae dichotomous key

1.  Butomus umbellatus L. E

flowering-rush. CT, MA, ME, VT; locally common in the Lake Champlain Valley, rare elsewhere. Marshes, lake and stream borders.

Native to North America?

No

Family

Butomaceae

Genus

Butomus