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Sagittaria graminea — grass-leaved arrowhead

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Facts

Native to freshwater shorelines and shallow water in eastern North America, grass-leaved arrowhead is a popular ornamental aquatic plant, and as such has been introduced outside its range, both within and outside North America. In some cases it has become invasive. Several parts of the plant are edible, but it is not as widely used for food as northern arrowhead (Sagittaria cuneata) or common arrowhead (S. latifolia).

Habitat

Fresh tidal marshes or flats, lacustrine (in lakes or ponds), riverine (in rivers or streams), shores of rivers or lakes, wetland margins (edges of wetlands)

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
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf position
the leaves are all submerged underwater
Leaf arrangement
the leaves are growing only at the base of the plant (basal)
Leaf blade length
64–350 mm
Petal or sepal number
there are three petals, sepals, or tepals in the flower
Petal color
white
Specific leaf type
the leaf is not divided, rather the blade is made up of one segment
Floating leaf shape
NA
Underwater leaf blade width
5–10 mm
Fruit type (general)
the fruit is dry but does not split open when ripe
Underwater leaf length
64–350 mm
Show all characteristics

  • Clonal plantlets

    Turion length
    0 mm

  • Flowers

    Anther color
    there is a noticeable pink, reddish or purplish tint to the anthers
    Anther length
    0.6–1 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
    3–36
    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
    25–210 mm
    Inflorescence type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Inflorescence width
    10–80 mm
    Length of flower stalk
    5–50 mm
    Length of peduncle
    65–297 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    At least 0
    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
    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
    10–20 mm
    Petal number
    3
    Petal or sepal number
    there are three petals, sepals, or tepals in the flower
    Pistil number
    • 0
    • 6 or more
    Sepal appearance
    the sepals resemble leaves in color and texture
    Sepal length
    3–6 mm
    Sepal number
    3
    Sepals fused only to sepals
    the sepals are separate from one another
    Spur length
    0 mm
    Stamen length
    1.2–2 mm
    Stamen number
    • 0
    • 12
    • 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
    At least 0

  • Fruits or seeds

    Fruit beak length
    0.1–0.3 mm
    Fruit length
    1.5–2.8 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)
    Fruit width
    1.1–1.5 mm

  • 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 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
    NA
    Floating leaf blade width
    0 mm
    Floating leaf length
    0 mm
    Floating leaf shape
    NA
    Floating leaf tip
    NA
    Floral bract form
    the bracts are roughly as lobed as the foliage leaves
    Floral bract length
    3–15 mm
    Leaf arrangement
    the leaves are growing only at the base of the plant (basal)
    Leaf blade length
    64–350 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
    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 air passage number
    At least 1439
    Underwater leaf air passage relative width
    At least 4336
    Underwater leaf air passage row number
    0
    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
    64–350 mm
    Underwater leaf stalk
    yes
    Underwater leaf stalk length
    64–350 mm
    Underwater leaf tip shape
    the tip of the underwater leaf is acute (sharply pointed)
    Veins in floating leaf
    0

  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • edges of wetlands
    • fresh tidal marshes or flats
    • in lakes or ponds
    • in rivers or streams
    • 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)

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
unranked (S-rank: SNR)

var. graminea

Massachusetts
unranked (S-rank: SNR)
Rhode Island
extremely rare (S-rank: S1), concern (code: C)

From Flora Novae Angliae dichotomous key

4.  Sagittaria graminea Michx. var. graminea N

grass-leaved arrowhead. Sagittaria eatonii J.G. Sm. • CT, MA, ME, NH, RI, VT; throughout. Shorelines and shallow water of lakes, streams, and pools, including fresh-tidal river shores.

Native to North America?

Yes

Sometimes confused with

Sagittaria rigida:
leaf blades, when formed, narrow-lanceolate to broad-lanceolate and lowest whorl of flowers borne on evident stalks (vs. S. graminea, with leaf blades, when formed, mostly elliptic to oval and lowest whorl of flowers unstalked or borne on very short stalks).

Synonyms

  • Sagittaria eatonii J.G. Sm.

Family

Alismataceae

Genus

Sagittaria