• You are here:
• Full Key
• Aquatic plants
• Water plants with leaves and stems
• Butomus umbellatus

Butomus umbellatus — flowering-rush

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

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)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae