- You are here:
- Full Key
- Aquatic plants
- Water plants with leaves and stems
- Myriophyllum farwellii
Myriophyllum farwellii — Farwell's water-milfoil
Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.
Facts
Farwell's water-milfoil is named after its discoverer, the prominent American botanist Oliver Atkins Farwell (1868-1944). It is a native milfoil, and protected in some New England states.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
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.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf position
- the leaves are all submerged underwater
- Leaf arrangement
-
- alternate: there is one leaf per node along the stem
- whorled: there are three or more leaves per node along the stem
- Leaf blade length
- 10–25 mm
- Petal or sepal number
- there are four petals, sepals, or tepals in the flower
- Petal color
- purple
- 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
- 10–25 mm
-
Flowers
- Anther length
- 0.4 mm
- Carpels fused
- the carpels are fused to one another
- Flower lower lip length
- 0 mm
- Flower position
- the flowers are below 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 flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
- 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
- the petals are thin and delicate, and pigmented (colored other than green or brown)
- Petal color
- purple
- Petal fringed edges
- the petals are fringed
- Petal fusion
- the perianth parts are separate
- Petal length
- 1 mm
- Petal number
- 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 number
- 4
- Stamens fused to petals
- the stamens are not fused to the petals or tepals
- Style number
- 4
-
Fruits or seeds
- Fruit length
- 2–2.5 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
- 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 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 much more lobed, or much less lobed, than the foliage leaves
- Floral bract length
- 0.4 mm
- Leaf arrangement
-
- alternate: there is one leaf per node along the stem
- whorled: there are three or more leaves per node along the stem
- Leaf blade length
- 10–25 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
- 5–12
- Leaf-like branch shape
- the leaf-like branches are round
- 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 are either smooth and without teeth, or with tiny, outward-pointing teeth
- 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 ovate (widest below the middle and broadly tapering at both ends)
- the underwater leaf blade is triangular, with the stalk or attachment point on one of the sides
- Underwater leaf length
- 10–25 mm
- Underwater leaf stalk
- yes
- Veins in floating leaf
- 0
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
-
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, invasive, prohibited
- Rhode Island
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- rare (S-rank: S2)
From Flora Novae Angliae dichotomous key
3. Myriophyllum farwellii Morong N
Farwell’s water-milfoil. CT, MA, ME, NH, RI, VT. Still or slow-moving, circumneutral to basic water of lakes and rivers.
Native to North America?
Yes