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Landoltia punctata — spotted-duck-meal

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Facts

Spotted-duck-meal is a native member of the duckweed family that reaches the northern edge of its range in Massachusetts. This tiny aquatic plant has "leaves" (thalli) with 5-7 veins, and about 2-7 dangling roots, all of which puncture the tiny scale at the base of the leaves. It inhabits high-nutrient waters of lakes and rivers.

Habitat

Lacustrine (in lakes or ponds), riverine (in rivers or streams)

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
aquatic
New England state
Massachusetts
Roots
there are two or more roots per thallus
Thallus shape in cross-section
the thallus is somewhat flattened on at least one side in cross-section
Thallus length
1.5–8 mm
Thallus shape
the thallus is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
Thallus dimensions
1.5–2
Veins on upper surface
3–7
Show all characteristics
  • Flowers

    Scale surrounding flower
    yes
    Stamen number
    2
  • Fruits or seeds

    Fruit length
    0.8–1 mm
    Seed surface ribbed
    the seed surface has ribs running from end to end
  • Growth form

    Root length
    Up to 70 mm
    Root number
    1–12
    Roots
    there are two or more roots per thallus
    Roots perforating basal scale
    all the roots protrude through the basal scale
    Thallus dimensions
    1.5–2
    Thallus edge
    the edge of the thallus is smooth (without teeth) near the tip
    Thallus length
    1.5–8 mm
    Thallus shape
    the thallus is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
    Thallus shape in cross-section
    the thallus is somewhat flattened on at least one side in cross-section
    Thallus with red pigment
    yes
    Turions
    no
  • Leaves

    Papilla on thallus
    no
    Veins on upper surface
    3–7
  • Place

    Habitat
    aquatic
    New England state
    Massachusetts
    Specific habitat
    • in lakes or ponds
    • in rivers or streams

Wetland status

Occurs only in wetlands. (Wetland indicator code: OBL)

In New England

Distribution

Connecticut
absent
Maine
absent
Massachusetts
present
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation status

None

From Flora Novae Angliae dichotomous key

1.  Landoltia punctata (G.F.W. Mey.) Les & D.J. Crawford E

spotted-duck-meal. Lemna punctata G.F.W. Mey.; Spirodela punctata (G.F.W. Mey.) 
C.H. Thompson • MA. Mesotrophic to eutrophic waters of lakes and rivers.

Native to North America?

Yes

Sometimes confused with

Spirodela polyrhiza

Family

Araceae

Genus

Landoltia