Lemna minuta Kunth

least duckweed

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Least duckweed is a tiny aquatic plant that reaches the northern edge of its rather patchy (disjunct) range on Martha's Vineyard Island in Massachusetts. To tell this species from other duckweeds, look closely at the "leaves" (thalli) with a hand lens. They will have a single vein that only extends about 2/3 of the length of the thallus. They will be solitary or paired (not form clusters), and their bases are symmetrical.

Habitat

Lacustrine (in lakes or ponds)

Characteristics

Habitat
aquatic
New England state
Massachusetts
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
0.8–4 mm
Thallus shape
the thallus is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
Thallus dimensions
1–2
Veins on upper surface
1
Show All Characteristics
  • Flowers
    Scale surrounding flower
    no
    Stamen number
    2
  • Fruits or seeds
    Fruit length
    0.6–1 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
    1–2
    Thallus edge
    the edge of the thallus is smooth (without teeth) near the tip
    Thallus length
    0.8–4 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 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
    Massachusetts
    Specific habitat
    in lakes or ponds

Wetland Status

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

New England Distribution and Conservation Status

Distribution

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

Conservation Status

None

Native to North America?

Yes

Sometimes Confused With

Lemna valdiviana:
vein usually extending past aerenchyma tissue, extending at least 3/4 of the distance from the root node to the tip of the thallus, and thalli 2–4 mm long, 1.3–3 times as long as wide, elliptic to lanceolate or obovate (vs. L. minuta, with the vein usually not extending past aerenchyma tissue, extending less than 2/3 of distance from root node to tip of thallus, thalli mostly 1–2.5 mm long, 1–2 times as long as broad, broad-elliptic to broad-oblong or obovate (vs. L. valdiviana, with the ).

Synonyms

  • Lemna minima Phil. ex Hegelm.
  • Lemna minuscula Herter
  • Lemna valdiviana Phil. var. minima Hegelm.

Family

Araceae

Genus

Lemna

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Information from Dichotomous Key of Flora Novae Angliae

2.  Lemna minuta Kunth E

least duckweed. Lemna minima Phil. ex Hegelm.; L. minuscula Herter; L. valdiviana Phil. var. minima Hegelm. • MA. Pools. Lemna minuta growing in shade often has slightly longer thalli that are more transparent than those growing in sun. Further, shade-grown plants sometimes grow in connected clusters of up to four plants, making shade grown plants much harder to differentiate from L. valdiviana. Relative root length is one of the most important characters and appears to be stable (i.e., not environmentally controlled).