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• Sagittaria montevidensis

Sagittaria montevidensis — spongy-leaved arrowhead

Facts

Spongy-leaved arrowhead inhabits tidal river shores, typically on mud flats. Our subspecies is endemic to a small portion of the northeastern coast. The name refers to the thick, spongy petioles that distinguish this species from other arrowheads (Sagittaria).

Habitat

Fresh tidal marshes or flats, 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 color

  the anthers show no hint of a pink, reddish or purplish tint

  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

  Filament surface

  the filament surface has rough hairs or scales on it

  Flower bract length

  4–34 mm

  Flower bracts

  there are bracts associated with the flower

  Flower orientation

  the flowers point upward or spread or curve outward

  Flower petal color

  white

  Flower petal length

  7–15 mm

  Flower shape

  the flower is flattened or platter-shaped

  Flower symmetry

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

  Form of style

  the flower has two or more completely separate styles

  Fringed petal edges

  the petals are not fringed

  Hairs on flower stalk

  the flower stalk has no hairs on it

  Inflorescence hair glands

  the axis of the inflorescence has no hairs on it

  Inflorescence length

  15–280 mm

  Inflorescence type

  • the inflorescence is a panicle (branched with the individual flowers on stalks)
  • the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)

  Inflorescence width

  15–150 mm

  Length of flower stalk

  5–42 mm

  Length of peduncle

  150–470 mm

  Marks on petals

  there are no noticeable marks on the petals

  Nectar spur

  the flower has no nectar spurs

  Number of carpels

  At least 3

  Number of pistils

  6 or more

  Number of sepals and/or petals

  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 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 base

  the petal narrows gradually or does not narrow at the base

  Petal fusion

  the perianth parts are separate

  Petal hairs on inner/upper surface

  there are no hairs on the inner/upper petal surface

  Petal nectaries

  the petals do not have nectaries

  Sepal appearance

  the sepals resemble leaves in color and texture

  Sepal length

  4–12 mm

  Sepal orientation

  • the sepals are pressed against the plant, or jutting stiffly upward
  • the sepals are slightly curved outwards from the plant

  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 number

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

  Stamen position relative to petals

  NA

  Stamen types

  the stamens within a cycle are all similar

  Stamens fused

  the stamens are not fused to one another

  Stamens fused outwards

  the stamens are not fused to the petals or tepals

  Style petal-like

  the style is not broad and flattened like a petal

  Tepals

  the petals and sepals are different in size and color

• Fruits or seeds

  Berry color

  NA

  Capsule ridges

  NA

  Fruit beak length

  0.4–0.8 mm

  Fruit compartments

  there is only one locule in the fruit

  Fruit cross-section

  the fruit is at least somewhat flattened

  Fruit length

  2–4.3 mm

  Fruit stalk orientation

  the fruits curve or droop downwards

  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)

  Fruit width

  0.7–1.5 mm

  Other markings on berry

  NA

• Glands or sap

  Sap

  the sap is milky and opaque, and may be white or colored

• Growth form

  Lifespan

  the plant lives only a single year or less

  Root septa

  the roots have transverse septa

  Underground organs

  • the plant has a rhizome (a horizontal underground stem with roots growing from it)
  • the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms

• Leaves

  Hairs on underside of leaf blade

  the underside of the leaf is not hairy, or has very few hairs

  Hairs on upper side of leaf blade

  the upper side of the leaf is not hairy, or has very few hairs

  Leaf arrangement

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

  Leaf blade basal lobes

  • the leaf blades are lobed at their bases
  • the leaf blades do not have basal lobes

  Leaf blade base

  • the leaf has a distinct leaf stalk (petiole)
  • the leaf has no stalk

  Leaf blade base shape

  • The base of the leaf blade is cordate (heart-shaped, with rounded lobes) or sagittate (arrow-shaped, with pointed, backward-facing lobes)
  • the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow

  Leaf blade bloom

  the underside of the leaf blade has no noticeable waxy or powdery bloom

  Leaf blade cross-section

  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

  25–175 mm

  Leaf blade orientation

  the upper surface of the leaf blade faces the stem of the plant

  Leaf blade shape

  • the leaf blade is cordate (heart-shaped with backward-facing rounded lobes), or sagittate (arrow-shaped with backward-facing pointed lobes)
  • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
  • the leaf blade is linear (very narrow with more or less parallel sides)
  • the leaf blade is spatulate (spoon-shaped; narrow near the base, then suddenly widening to a rounded tip)

  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 acute (sharply pointed)
  • 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

  6–22 mm

  Leaf stalk length

  0–550 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

  Specific habitat

  • fresh tidal marshes or flats
  • 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 interior

  the flowering stem is solid

  Flowering stem leaves

  there are no true leaves 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