Myriophyllum aquaticum (Vell.) Verdc.

Parrot's-feather water-milfoil

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Parrot's-feather water-milfoil is introduced from South America and has become a serious pest in many parts of the world, forming dense mats in shallow water of ponds and lakes. It spreads rapidly from rhizome fragments. Fortunately, New England remains largely free of this invader, which is found only in parts of Connecticut.

Habitat

Anthropogenic (man-made or disturbed habitats), lacustrine (in lakes or ponds)

Characteristics

Habitat
aquatic
New England state
  • Connecticut
  • Massachusetts
Leaf position
the leaves are all submerged underwater
Leaf arrangement
whorled: there are three or more leaves per node along the stem
Leaf blade length
8–45 mm
Petal or sepal number
there are four petals, sepals, or tepals in the flower
Petal color
NA
Specific leaf type
the leaf is once pinnately divided and the segments are very narrow, each side providing the appearance of a comb
Floating leaf shape
NA
Fruit type (general)
the fruit is dry and splits open when ripe
Underwater leaf length
8–45 mm
Show All Characteristics
  • Flowers
    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 type
    the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
    Length of flower stalk
    0 mm
    Length of peduncle
    0 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    4
    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
    NA
    Petal color
    NA
    Petal fringed edges
    NA
    Petal fusion
    NA
    Petal hairs on inner/upper surface
    NA
    Petal length
    0–5 mm
    Petal number
    0–4
    Petal or sepal number
    there are four petals, sepals, or tepals in the flower
    Pistil number
    1
    Sepal appearance
    the sepals resemble leaves in color and texture
    Sepal number
    4
    Spur length
    0 mm
    Stamen length
    1.2–2 mm
    Stamen number
    8
    Stamen position relative to petals
    NA
    Stamens fused to petals
    the stamens are not fused to the petals or tepals
    Style length
    0 mm
    Style number
    0
  • Fruits or seeds
    Fruit length
    1.5–2 mm
    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a schizocarp (when dry it splits into sections, each holding one or more seeds)
    Fruit width
    1.8–1.2 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
    Roots floating in water
    there are no clusters of roots floating in the water
    Turions
    the plant has turions
    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 1380 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
    25–35 mm
    Leaf arrangement
    whorled: there are three or more leaves per node along the stem
    Leaf blade length
    8–45 mm
    Leaf blade veins
    the lateral veins radiate from the base and continue to spread away from the centerline of the leaf, or branch off the central vein at intervals
    Leaf position
    the leaves are all submerged underwater
    Leaf special features
    none of the mentioned special features are present
    Leaf-like branch segments
    8–30
    Leaf-like branch shape
    the leaf-like branches are flat
    Specific leaf type
    the leaf is once pinnately divided and the segments are very narrow, each side providing the appearance of a comb
    Staminate bract edge (Myriophyllum)
    the edges of the staminate bracts have either forward-pointing teeth, or are pinnately lobed (with lobes projecting from both sides of the central axis of the leaf)
    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 blade edges
    the underwater leaf blades are lobed
    Underwater leaf blade shape
    • the underwater leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the underwater leaf blade)
    • the underwater leaf blade is oblong (rectangular but with rounded ends)
    Underwater leaf length
    8–45 mm
    Underwater leaf stalk
    yes
    Underwater leaf stalk length
    5–7 mm
    Veins in floating leaf
    0
  • Place
    Habitat
    aquatic
    New England state
    • Connecticut
    • Massachusetts
    Specific habitat
    • in lakes or ponds
    • man-made or disturbed habitats
  • 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

Distribution

Connecticut
present, invasive, prohibited
Maine
absent
Massachusetts
absent
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation Status

None

Native to North America?

No

Sometimes Confused With

Myriophyllum verticillatum:
flowers subtended by bracts less than 15 mm long, with marginal teeth or divisions shorter than 4 mm, the bracts conspicuously reduced in size and less divided than the submersed leaves, and submersed leaves with petioles 0–2 mm long (vs. M. aquaticum, with flowers subtended by bracts mostly 25–35 mm long with uniform linear divisions 4–8 mm long, the bracts +/- similar in size and division to the submersed leaves, and submersed leaves with petioles 5–7 mm long).

Synonyms

  • Enydria aquatica Vell.
  • Myriophyllum brasiliense Camb.
  • Myriophyllum proserpinacoides Gillies ex Hook.

Family

Haloragaceae

Genus

Myriophyllum

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Information from Dichotomous Key of Flora Novae Angliae

2.  Myriophyllum aquaticum (Vell.) Verdc. E

Parrot’s-feather water-milfoil. Enydria aquatica Vell.; Myriophyllum brasiliense Camb.; 
 M. proserpinacoides Gillies ex Hook. & Arn. • CT. Ponds, often those in areas of habitation.