Description:

• Small, usually discoid aquatics, floating or slightly submerged and rising to surface at anthesis
• Roots solitary, rarely 0, fairly long, bearing a basal sheath and calyptra
• Fronds solitary or several cohering for shorter or longer periods, regular or somewhat irregular, in various rounded shapes to linear-lanceolate, flat or gibbous dorsally with a median row of papillae and 1-5(-7) nerves, without pigment cells in the epidermis; margin entire or rarely denticulate; dorsal and ventral scale wanting
• Budding pouch marginal, rarely ventral or dorsal
• Inflorescence of 1 female and 2 male flowers enclosed in a membranous sheath
• Anther 2-thecous
• Utricle with 1-7 ovules
• Seeds longitudinally ribbed with transverse striations, rarely smooth
• x = 10 (high polyploidy)

Nomenclature:

• Lemna L.
  • Linnaeus: 970 (1753)
  • Den Hartog & Van der Plas: 360 (1970)
  • Landolt: 471 (1986)
  • Cook: 113 (1990)

Distribution & Notes:

• Global: Species 13, almost cosmopolitan
• Southern Africa: Species 3, common in most water bodies, usually gregarious, can become a problem plant in water high in organic matter
  • Seeds, turions or complete fronds dispersed by water and also by adhesion to animals, mostly birds