Myriophyllum aquaticum — Parrot's-feather water-milfoil
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Facts
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)
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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enlargeCharacteristics
- 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
-
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)
In New England
Distribution
- Connecticut
- present, invasive, prohibited
- Maine
- absent
- Massachusetts
- present, invasive, prohibited
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
2. Myriophyllum aquaticum (Vell.) Verdc. E
Parrot’s-feather water-milfoil. Enydria aquatica Vell.; Myriophyllum brasiliense Camb.; M. proserpinacoides Gillies ex Hook. & Arn. • CT, MA. Ponds, often those in areas of habitation.
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.