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Brasenia schreberi — water-shield

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Facts

Water-shield is a widespread species that is distinctive due to the thick coating of gelatinous slime covering the young stems, buds, and the undersides of young leaves. It is cultivated in China and Japan where the mucilage-covered shoots are eaten.

Habitat

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

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
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
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade length
35–135 mm
Petal or sepal number
there are three petals, sepals, or tepals in the flower
Petal color
purple
Specific leaf type
the leaf is not divided, rather the blade is made up of one segment
Floating leaf shape
the leaf blade is elliptic (widest near the middle and tapering at both ends)
Underwater leaf blade width
0 mm
Fruit type (general)
the fruit is dry but does not split open when ripe
Underwater leaf length
0 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
    4 mm
    Carpels fused
    the carpel is solitary or (if 2 or more) the carpels are not fused to one another
    Flower lower lip length
    0 mm
    Flower number
    1
    Flower position
    the flowers are above the surface of the water
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    Inflorescence type
    • the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
    • the inflorescence has only one flower on it
    Inflorescence width
    20 mm
    Length of flower stalk
    60–100 mm
    Length of peduncle
    60–100 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    4–8
    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 green and/or leafy in texture
    Petal color
    purple
    Petal fringed edges
    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
    10–20 mm
    Petal number
    3
    Petal or sepal number
    there are three petals, sepals, or tepals in the flower
    Pistil number
    • 4
    • 5
    • 6 or more
    Sepal appearance
    the sepals resemble petals in color and texture
    Sepal length
    10–20 mm
    Sepal number
    3
    Sepals fused only to sepals
    the sepals are separate from one another
    Spur length
    0 mm
    Stamen length
    5–10 mm
    Stamen number
    13 or more
    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
    4–18

  • Fruits or seeds

    Fruit length
    6–10 mm
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    Fruit type (specific)
    the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)

  • Glands or sap

    Oil glands on nodes
    none of the nodes have oil glands
    Sap
    the sap is milky and opaque, and may be white or colored

  • 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 3854 mm
    Bracts
    neither the flowers nor their pedicels have bracts
    Floating leaf basal lobes
    no
    Floating leaf blade width
    20–80 mm
    Floating leaf length
    35–135 mm
    Floating leaf shape
    the leaf blade is elliptic (widest near the middle and tapering at both ends)
    Floating leaf tip
    the tip of the floating leaf blade is rounded, with no point
    Floral bract form
    NA
    Floral bract length
    0 mm
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade length
    35–135 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 blade width
    35–60 mm
    Leaf position
    some of the leaves are floating at the surface of the water
    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 air passage number
    At least 4335
    Underwater leaf air passage relative width
    At least 4336
    Underwater leaf air passage row number
    0
    Underwater leaf blade edges
    NA
    Underwater leaf blade shape
    NA
    Underwater leaf blade veins
    0
    Underwater leaf blade width
    0 mm
    Underwater leaf length
    0 mm
    Underwater leaf stalk
    NA
    Underwater leaf stalk length
    0 mm
    Underwater leaf tip shape
    NA

  • 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)

In New England

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
widespread (S-rank: S5)

From Flora Novae Angliae dichotomous key

1.  Brasenia schreberi J.F. Gmel. N

water-shield. Brasenia peltata Pursh • CT, MA, ME, NH, RI, VT. Still or slow-moving water of lakes and streams, usually oligotrophic to mesotrophic.

Native to North America?

Yes

Sometimes confused with

Cabomba caroliniana:
leaves strongly dimorphic--submersed, opposite, highly dissected ones and floating, alternate, simple ones, flowers with 3-6 stamens, and underwater parts of plant barely coated with mucilage (vs. B. schreberi, with leaves monomorphic, all alternate and floating, flowers with mostly 18-36 stamens, and underwater parts of plant heavily coated with mucilage).

Synonyms

  • Brasenia peltata Pursh

Family

Nymphaeaceae

Genus

Brasenia