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Native Plant Trust: Go Botany Discover thousands of New England plants

Eriocaulon aquaticum — seven-angled pipewort

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Facts

Seven-angled pipewort is found in wet soil or shallow water of lakes and slow-moving rivers in all New England states. While many other aquatic plants are wind- or water-pollinated, seven-angled pipewort has a nectar gland near the tip of each petal, to attract insect pollinators.

Habitat

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

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
basal: the leaves are growing only at the base of the plant
Leaf blade length
10–400 mm
Petal or sepal number
there are two petals, sepals, or tepals in the flower
Petal color
  • other
  • 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
2–5 mm
Fruit type (general)
the fruit is dry and splits open when ripe
Underwater leaf length
10–400 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
    Carpels fused
    the carpels are fused to one another
    Flower lower lip length
    0 mm
    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
    4–6 mm
    Inflorescence type
    • the inflorescence is a pseudanthium (a cluster of small flowers that appear to be one flower (e.g., flower head of composites)
    • the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
    Inflorescence width
    4–10 mm
    Length of flower stalk
    0 mm
    Length of peduncle
    30–200 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    0–2
    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
    • other
    • white
    Petal fringed edges
    the petals are not fringed
    Petal fusion
    • the perianth parts are fused to form a tube, cup, or bell shape
    • the perianth parts are separate
    Petal hairs on inner/upper surface
    there are hairs on the inner/upper petal surface
    Petal length
    0.5–1.5 mm
    Petal number
    2
    Petal or sepal number
    there are two petals, sepals, or tepals in the flower
    Pistil number
    • 0
    • 1
    Sepal appearance
    the sepals resemble leaves in color and texture
    Sepal length
    1.5 mm
    Sepal number
    2
    Sepals fused only to sepals
    • the sepals are fused to each other (not other flower parts), at least near their bases
    • the sepals are separate from one another
    Spur length
    0 mm
    Stamen number
    • 0
    • 4
    Stamen position relative to petals
    NA
    Stamens fused to petals
    the stamens are not fused to the petals or tepals
    Style number
    0–1

  • Fruits or seeds

    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)

  • 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 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
    there are only slender roots on the plant

  • 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
    1–1.5 mm
    Leaf arrangement
    basal: the leaves are growing only at the base of the plant
    Leaf blade length
    10–400 mm
    Leaf blade veins
    the lateral veins are parallel or slightly arched in the direction of the tip
    Leaf blade width
    2–5 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 1440
    Underwater leaf air passage relative width
    At least 1442
    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)
    • the underwater leaf blade is subulate (awl-shaped; narrowly tapering from the base to the tip)
    Underwater leaf blade veins
    3–9
    Underwater leaf blade width
    2–5 mm
    Underwater leaf length
    10–400 mm
    Underwater leaf stalk
    no
    Underwater leaf stalk length
    0 mm
    Underwater leaf tip shape
    the tip of the underwater leaf is acuminate (tapers to a long, thin point)
    Veins in floating leaf
    0

  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • 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
widespread (S-rank: S5)

From Flora Novae Angliae dichotomous key

1.  Eriocaulon aquaticum (Hill) Druce N

seven-angled pipewort. Cespa aquatica Hill; Eriocaulon pellucidum Michx. • CT, MA, ME, NH, RI, VT. Wet soil or shallow water of lakes and slow-moving rivers. The name Eriocaulon septangulare Withering, which has been used for this species, is invalid.

Native to North America?

Yes

Sometimes confused with

Eriocaulon parkeri:
inflorescences hemispherical, 3-4 mm wide, with bractlets that are sparsely pubescent with clavate hairs, and each rosette producing 1-4 scapes with 4 or 5 ridges (vs. E. aquaticum, with inflorescences subglobose, 4-10 mm wide, with bractlets that are pubescent with clavate hairs, and each rosette producing usually a single flowering scape with mostly 5-7 ridges).

Synonyms

  • Cespa aquatica Hill
  • Eriocaulon pellucidum Michx.

Family

Eriocaulaceae

Genus

Eriocaulon