Lemna valdiviana — pale 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
Although Pale duckweed is a widespread native species found in several New England states, it is considered endangered in New Hampshire. The "leaves" (thalli) of this aquatic plant have a prominent midvein that extends nearly the length of the leaf, and their bases are asymmetrical.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
Characteristics
- Habitat
- aquatic
- New England state
-
- Connecticut
- Massachusetts
- New Hampshire
- Rhode Island
- 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
- 1–5 mm
- Thallus shape
-
- the thallus is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the thallus is ovate (egg-shaped)
- Thallus dimensions
- 1.3–3
- Veins on upper surface
- 1
-
Flowers
- Scale surrounding flower
- no
- Stamen number
- 2
-
Fruits or seeds
- Fruit length
- 1–1.35 mm
- Seed surface ribbed
- the seed surface has ribs running from end to end
-
Growth form
- Root length
- Up to 15 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
- 1.3–3
- Thallus edge
- the edge of the thallus is smooth (without teeth) near the tip
- Thallus length
- 1–5 mm
- Thallus shape
-
- the thallus is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- 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 with red pigment
- no
- Turions
- no
-
Leaves
- Papilla on thallus
-
- no
- yes
- Veins on upper surface
- 1
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Massachusetts
- New Hampshire
- Rhode Island
- 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
- absent
- 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.
- Connecticut
- unrankable (S-rank: SU)
- Massachusetts
- unranked (S-rank: SNR)
- New Hampshire
- historical (S-rank: SH), endangered (code: E)
- Rhode Island
- extremely rare (S-rank: S1), concern (uncertain) (code: C*)
From the dichotomous key of Flora Novae Angliae
6. Lemna valdiviana Phil. NC
pale duckweed. Lemna torreyi Austin • CT, MA, NH, RI. Mesotrophic to eutrophic waters of lakes, rivers, beaver flowages, and pools.