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• Sparganium emersum

Sparganium emersum — simple-stemmed bur-reed

Facts

Simple-stemmed bur-reed can form large stands and prefers shallow water with a neutral to alkaline pH. There are two varieties in New England.

Habitat

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

Characteristics

• Clonal plantlets

  Axillary bulblets

  there are no bulblets being produced in axils

• Flowers

  Anther attachment

  the anther is attached by its base to the filament

  Anther length

  Up to 1.6 mm

  Bulblets replace flowers

  there are no bulblets where the flowers are located

  Carpels fused

  the carpel is solitary or (if 2 or more) the carpels are not fused to one another

  Flower bracts

  there are bracts associated with the flower

  Flower petal color

  • green to brown
  • white

  Flower symmetry

  there are two or more ways to evenly divide the flower (the flower is radially symmetrical)

  Form of style

  the style is narrow at the tip and unbranched

  Fringed petal edges

  the petals are not fringed

  Hairs on flower stalk

  NA

  Inflorescence type

  the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)

  Marks on petals

  there are no noticeable marks on the petals

  Nectar spur

  the flower has no nectar spurs

  Number of carpels

  1

  Number of pistils

  1

  Number of sepals and/or petals

  • there are five petals, sepals or tepals in the flower
  • there are four petals, sepals or tepals in the flower
  • there are six petals, sepals or tepals in the flower
  • there are three petals, sepals or tepals in the flower

  Number of styles

  1

  Ovary position

  the ovary is above the point of petal and/or sepal attachment

  Petal appearance

  the petals are green and/or leafy in texture

  Petal fusion

  the perianth parts are separate

  Sepal appearance

  the sepals resemble leaves in color and texture

  Sepals fused only to sepals

  the sepals are separate from one another

  Spathe

  the plant does not have a spathe

  Spathe form

  NA

  Spathe length

  0 mm

  Stamen length

  Up to 5.6 mm

  Stamen number

  • 1 or 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8

  Stamen position relative to petals

  NA

  Stamens fused outwards

  the stamens are not fused to the petals or tepals

  Style length

  Up to 1 mm

  Style petal-like

  the style is not broad and flattened like a petal

  Tepals

  the petals and sepals are similar in size and color

• Fruits or seeds

  Berry color

  NA

  Capsule ridges

  NA

  Fruit beak length

  2–4.5 mm

  Fruit compartments

  there is only one locule in the fruit

  Fruit cross-section

  the fruit is at least somewhat flattened

  Fruit length

  3–4 mm

  Fruit type (general)

  the fruit is dry but does not split open when ripe

  Fruit type (specific)

  • the fruit is a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
  • the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)

  Fruit width

  1.5–2 mm

  Other markings on berry

  NA

• Glands or sap

  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

  Underground organs

  • the plant has a rhizome (a horizontal underground stem with roots growing from it)
  • there are only slender roots on the plant

• Leaves

  Leaf arrangement

  • alternate: there is one leaf per node along the stem
  • basal: the leaves are growing only at the base of the plant

  Leaf blade basal lobes

  the leaf blades do not have basal lobes

  Leaf blade cross-section

  • the leaf blade is U- or V-shaped
  • the leaf blade is more or less flat in cross-section

  Leaf blade faces

  both surfaces of the leaf blade are exposed

  Leaf blade form

  Fully-formed (i.e., expanded), +/- green leaf blades are found somewhere on the plant

  Leaf blade length

  Up to 2000 mm

  Leaf blade shape

  the leaf blade is linear (very narrow with more or less parallel sides)

  Leaf blade surface colors

  the upper side of the leaf blade is relatively uniform in color

  Leaf blade tip

  • the tip of the leaf blade is obtuse (bluntly pointed)
  • the tip of the leaf blade is retuse (blunt or rounded, with a notch at the tip)
  • the tip of the leaf blade is rounded, with no point

  Leaf blade veins

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

  Leaf blade width

  4–18 mm

  Leaf type

  the leaves are simple (i.e., lobed or unlobed but not separated into leaflets

  Leaflet number

  0

  Stipule twining

  NA

  Stipules

  there are no stipules on this plant

• Place

  Habitat

  • aquatic
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont

  Specific habitat

  • in lakes or ponds
  • in rivers or streams
  • shores of rivers or lakes

• Scent

  Plant odor

  the leaves have no particular smell

• Stem, shoot, branch

  Flowering stem growth form

  the flowering stem is held upright

  Flowering stem leaves

  there is at least one fully-formed leaf on the flowering stem

  Stem hairs

  the stem is nearly or completely hairless

Wetland status

Occurs only in wetlands. (Wetland indicator code: OBL)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae