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- Potamogeton pulcher
Potamogeton pulcher — spotted pondweed
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Facts
Spotted pondweed can be found in lakes, rivers, and even streams and pools in acidic swamps. Its black-spotted stems make it fairly distinctive. It is rare in northern New England.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams), swamps
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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Characteristics
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Leaf position
-
- some of the leaves are floating at the surface of the water
- 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
- 35–138 mm
- Petal or sepal number
- there are four petals, sepals, or tepals in the flower
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Floating leaf shape
-
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is orbicular (roughly circular, as wide as long)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- Underwater leaf blade width
- 60–165 mm
- Fruit type (general)
-
- the fruit is dry but does not split open when ripe
- the fruit is fleshy
- Underwater leaf length
- 35–138 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther length
- 0.8–1.4 mm
- 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 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
- 17–36 mm
- Inflorescence type
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Inflorescence width
- 8–11 mm
- Length of flower stalk
- At least 0 mm
- Length of peduncle
- 33–94 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 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 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
- 0.3–0.9 mm
- Fruit length
- 5–6.7 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
- 4.1–5 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
- there are no turions on the plant
- 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
- no
- Floating leaf blade width
- 11–44 mm
- Floating leaf length
- 25–85 mm
- Floating leaf shape
-
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is orbicular (roughly circular, as wide as long)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- Floating leaf tip
-
- the tip of the floating leaf blade is acute (sharply pointed)
- the tip of the floating leaf blade is rounded, with no point
- 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
- 35–138 mm
- Leaf blade veins
- the lateral veins are parallel or slightly arched in the direction of the tip
- Leaf blade width
- 60–165 mm
- Leaf position
-
- some of the leaves are floating at the surface of the water
- 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 firm or fibrous, and colored white, green or brown
- 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
- 2–5
- Underwater leaf blade edges
- the underwater leaf has smooth edges, without teeth
- Underwater leaf blade shape
- the underwater leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- Underwater leaf blade veins
- 7–19
- Underwater leaf blade width
- 60–165 mm
- Underwater leaf length
- 35–138 mm
- Underwater leaf stalk
- yes
- Underwater leaf stalk length
- 5–45 mm
- Underwater leaf tip shape
-
- the tip of the underwater leaf is acute (sharply pointed)
- the tip of the underwater leaf is obtuse (bluntly pointed)
- Veins in floating leaf
- 15–19
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
- swamps
-
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
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Maine
- extremely rare (S-rank: S1), threatened (code: T)
- Maine
- extremely rare (S-rank: S1), threatened (code: T)
- Massachusetts
- fairly widespread (S-rank: S4)
From Flora Novae Angliae dichotomous key
21. Potamogeton pulcher Tuckerman N
spotted pondweed. CT, MA, ME, NH, RI; rare in northern New England. Shallow, still or slow-moving, acidic to circumneutral water of lakes and rivers, including streams and pools within acid swamps.
2×21. Potamogeton amplifolius × Potamogeton pulcher → This rare pondweed hybrid is known from NH. It has smaller (though still somewhat arched) submersed blades than P. amplifolius (mostly 31–57 mm long, rather than 50–125 mm long), and there is some black spotting on the stems.
Native to North America?
Yes
Sometimes confused with
- Potamogeton amplifolius:
- submersed leaf blades ovate to broad-oblanceolate, with 19–49 veins, floating leaf blades with 27–49 veins, and stems red-brown-spotted (vs. P. pulcher, with submersed leaf blades narrow-lanceolate to lanceolate, with 7–19 veins, floating leaf blades with 15–19 veins, and stems black-spotted).