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• Aquatic plants
• Water plants with leaves and stems
• Limnobium spongia

Limnobium spongia — American spongeplant

Facts

American spongeplant is native to the southeastern states. It has thick, spongy, floating leaves and thinner emergent leaves that lack the spongy tissue. After fertilization, the peduncle curves down, so that the developing fruit is pushed underwater.

Habitat

Shores of rivers or lakes

Characteristics

• Clonal plantlets

  Turion length

  0 mm

• Flowers

  Anther color

  there is a noticeable pink, reddish or purplish tint to the anthers

  Anther length

  2–4 mm

  Carpels fused

  the carpels are fused to one another

  Flower lower lip length

  0 mm

  Flower number

  1–9

  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 length

  25–100 mm

  Inflorescence type

  the inflorescence is a monochasial cyme (an axis with a terminal flower, below it a branch with a terminal flower, this branch may itself have a branch and so on)

  Length of flower stalk

  30–100 mm

  Length of peduncle

  25–100 mm

  Nectar spur

  the flower has no nectar spurs

  Number of carpels

  6–9

  Ovary position

  the sepals and/or petals are attached above 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

  white

  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

  8–10 mm

  Petal number

  3–4

  Petal or sepal number

  there are three petals, sepals, or tepals in the flower

  Pistil number

  1

  Sepal appearance

  the sepals resemble petals in color and texture

  Sepal length

  7–10 mm

  Sepal number

  3

  Sepals fused only to sepals

  the sepals are separate from one another

  Spur length

  0 mm

  Stamen number

  • 10
  • 11
  • 12
  • 13 or more
  • 9

  Stamen position relative to petals

  NA

  Stamens fused

  • the stamens are fused to one another at or near their bases
  • the stamens are not fused to one another

  Stamens fused to petals

  the stamens are not fused to the petals or tepals

  Style number

  3–9

• Fruits or seeds

  Fruit length

  10–15 mm

  Fruit type (general)

  • the fruit is dry and splits open when ripe
  • the fruit is fleshy

  Fruit type (specific)

  the fruit is a berry (fleshy, with the wall enclosing one or more sections, with two or more seeds)

  Fruit width

  4–12 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

  the roots do not have transverse septa

  Turions

  there are no turions on the plant

• Leaves

  Bract position (Sparganium)

  NA

  Bracts

  the flowers or their pedicels have bracts at their bases

  Floating leaf basal lobes

  yes

  Floating leaf blade width

  20–50 mm

  Floating leaf length

  20–80 mm

  Floating leaf shape

  • the leaf blade is cordate (heart-shaped with backward-facing rounded lobes)
  • the leaf blade is orbicular (roughly circular, as wide as long)
  • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)

  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)
  • the tip of the floating leaf blade is obtuse (bluntly pointed)

  Floral bract form

  the bracts are roughly as lobed as the foliage leaves

  Floral bract length

  30–50 mm

  Leaf arrangement

  basal: the leaves are growing only at the base of the plant

  Leaf blade length

  20–80 mm

  Leaf blade veins

  the lateral veins are parallel or slightly arched in the direction of the tip

  Leaf blade width

  20–50 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 fused to leaf

  the stipules are not attached to the leaf blade at all

  Stipules

  the plant has stipules

  Trap-bladder length

  0 mm

  Underwater leaf air passage number

  At least 1440

  Underwater leaf air passage relative width

  At least 1441

  Underwater leaf blade edges

  the underwater leaf has smooth edges, without teeth

  Underwater leaf blade shape

  NA

  Underwater leaf blade veins

  0

  Underwater leaf blade width

  0 mm

  Underwater leaf length

  0 mm

  Underwater leaf stalk

  yes

  Underwater leaf stalk length

  20–250 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)
  • the tip of the underwater leaf is obtuse (bluntly pointed)

  Veins in floating leaf

  5–7

• Place

  Habitat

  • aquatic
  • wetlands

  New England state

  Connecticut

  Specific habitat

  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