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- Dichotomous Key
- Potamogetonaceae
- Potamogeton
- Potamogeton foliosus
Potamogeton foliosus — leafy pondweed
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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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Facts
Leafy pondweed is the only species of pondweed (Potamogeton) with linear leaves that also has an undulating wing-like keel on the fruits.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
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
- 13–82 mm
- Petal or sepal number
- there are four petals, sepals, or tepals in the flower
- Petal color
- brown
- 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
- 0.3–2.3 mm
- Fruit type (general)
-
- the fruit is dry but does not split open when ripe
- the fruit is fleshy
- Underwater leaf length
- 13–82 mm
-
Clonal plantlets
- Turion length
- 9–25 mm
-
Flowers
- 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
- 4–6
- 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
- 1.5–7 mm
- Inflorescence type
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Inflorescence width
- 2–5 mm
- Length of peduncle
- 3–37 mm
- Nectar spur
- the flower has no nectar spurs
- Number of carpels
- 4
- Ovary position
- the sepals and/or petals are attached below the ovary
- Palate on corolla
- no
- Petal and sepal arrangement
- the flower includes only one cycle of petals or sepals
- Petal appearance
- the petals are green and/or leafy in texture
- Petal color
- brown
- 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
- 0.6–1 mm
- Petal number
- 4
- Petal or sepal number
- there are four petals, sepals, or tepals in the flower
- Pistil number
- 4
- Sepal appearance
- NA
- Sepal length
- 0 mm
- Sepal number
- 0
- Sepals fused only to sepals
- NA
- Spur length
- 0 mm
- Stamen number
- 4
- Stamen position relative to petals
- NA
- Stamens fused to petals
- the stamens are fused near the bases of the petals or tepals
- Style number
- 4
-
Fruits or seeds
- Fruit beak length
- 0.2–0.6 mm
- Fruit length
- 1.4–2.7 mm
- Fruit type (general)
-
- the fruit is dry but does not split open when ripe
- the fruit is fleshy
- Fruit type (specific)
-
- the fruit is a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
- the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
- Fruit width
- 1.2–2.2 mm
-
Glands or sap
- Oil glands on nodes
-
- at least some of the nodes have pairs of oil glands
- 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 3854 mm
- Bracts
- neither the flowers nor their pedicels have bracts
- 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
- NA
- Floral bract length
- 0 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
- 13–82 mm
- Leaf blade veins
- the lateral veins are parallel or slightly arched in the direction of the tip
- Leaf blade width
- 0.3–2.3 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
- the stipules are delicate and translucent
- Stipule fused to leaf
- the stipules are not attached to the leaf blade at all
- Stipules
- the plant has stipules
- Stipules fused around stem
- the stipules do not forma closed tube around the stem
- Trap-bladder length
- 0 mm
- Underwater leaf air passage number
- At least 1440
- Underwater leaf air passage relative width
- At least 1442
- Underwater leaf air passage row number
- 0–2
- 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 veins
- 1–5
- Underwater leaf blade width
- 0.3–2.3 mm
- Underwater leaf length
- 13–82 mm
- Underwater leaf stalk
- no
- Underwater leaf stalk length
- 0 mm
- Underwater leaf tip shape
- the tip of the underwater leaf is acute (sharply pointed)
- 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)
New England distribution and conservation status
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)
- New Hampshire
- historical (S-rank: SH), endangered (code: E)
var. foliosus
- Massachusetts
- unranked (S-rank: SNR)
Native to North America?
Yes
Sometimes confused with
Family
Genus
From the dichotomous key of Flora Novae Angliae
8. Potamogeton foliosus Raf. ssp. foliosus N
leafy pondweed. Potamogeton foliosus Raf. var. genuinus Fern.; P. foliosus Raf. var. macellus Fern. • CT, MA, ME, NH, RI, VT. Shallow, still or slow-moving, circuneutral to basic water of lakes and rivers.