Lemna trisulca — ivy-leaved duckweed
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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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enlargeFacts
The leaf-like blade in ivy-leaved duckweed is called a thallus. Longer and narrower than common duckweed (Lemna minor), the two species are often found together scattered among emergent plants or matted together in floating mats in mesotrophic or eutrophic lakes and rivers. This species is absent from most of interior northern New England, except for Vermont's Lake Champlain Valley.
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
- Roots
- there is approximately one root per thallus
- Thallus shape in cross-section
- the thallus is somewhat flattened on at least one side in cross-section
- Thallus length
- 3–15 mm
- Thallus shape
- the thallus is ovate (egg-shaped)
- Thallus dimensions
- 2–3.5
- Veins on upper surface
- 1–3
-
Flowers
- Scale surrounding flower
- yes
- Stamen number
- 2
-
Fruits or seeds
- Fruit length
- 0.6–0.9 mm
- Seed surface ribbed
- the seed surface has ribs running from end to end
-
Growth form
- Root length
- 0–25 mm
- Root number
- 1
- Root sheath winged at base
- no
- Roots
- there is approximately one root per thallus
- Roots perforating basal scale
- there is no basal scale on the plant
- Thallus dimensions
- 2–3.5
- Thallus edge
- the edge of the thallus has tiny teeth near the tip
- Thallus length
- 3–15 mm
- Thallus shape
- the thallus is ovate (egg-shaped)
- Thallus shape in cross-section
- the thallus is somewhat flattened on at least one side in cross-section
- Thallus stalks
- the thallus has a stalk
- Thallus width
- 0.9–7.5 mm
- Thallus with red pigment
- yes
- Turions
- no
-
Leaves
- Papilla on thallus
- no
- Veins on upper surface
- 1–3
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
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
- extremely rare (S-rank: S1), endangered (code: E)
From the dichotomous key of Flora Novae Angliae
4. Lemna trisulca L. N
ivy-leaved duckweed. CT, MA, ME, NH, RI, VT; extending north in the Lake Champlain Valley but not found in a large portion of the interior of northern New England. Circumneutral, mesotrophic to eutrophic waters of lakes and rivers.