Wayne Armstrong's On-line Description of Lemna gibba (Lemnaceae)
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Lemna gibba


Inflated Duckweed or Windbags

Sp. Pl. 1: 970; 1753.


Roots: One root.

Shape of Plant Body: Flattened, orbicular-ovate in outline, often asymmetrical (oblique) at apex; dorsal surface with slight median ridge without distinct papules; ventral side often conspicuously inflated-gibbous, with distinct, large air spaces (often larger than 0.3 mm) and bordered (outlined) in reddish anthocyanin.

Size: 3-5 (6) mm long.

Veins: 3 (sometimes 5).

Budding Pouch Position: 2 lateral pouches on either side of basal end.

Flower (Fruit) Position: Within membranous, saclike (flasklike) spathe (open at top only) inside budding pouches.

Arrangement of Clonal Clusters: Solitary or several (2-5) attached.

Habitat: Freshwater ponds, marshes and quiet streams; also grows in slightly brackish cattail marshes bordering estuaries of San Diego County.

Range: Widespread in California but rarer in Pacific Northwest; generally replaced in higher mountains (and colder regions) by Lemna turionifera Landolt; widespread throughout tropical and temperate regions, including North and South America, Europe, Africa and Asia.

Other Information:

Degree of gibbosity may be influenced by environmental conditions; nongibbous forms with reduced air spaces difficult to identify; may be separated from L. minor L. by its yellowish-green more orbicular dorsal surface, often with asymmetrical apex and reddish anthocyanin mottling (L. turionifera has a more distinct midline row of dorsal papules, turions in fall, and is generally without dorsal anthocyanin mottling); the ovoid, one-seeded fruit (utricle) has 2 lateral winglike appendages (utricles of other Lemna spp. without lateral wings).

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