Description:

• Small to minute, glabrous, floating, freshwater herbs, forming a discoid, oblong, strap-shaped or globular body (frond), with or without roots, viviparous, gregarious, usually monoecious; annual fronds changing to turions under unfavourable conditions
• Roots, if present, with or without a basal sheath, with a large calyptra
• Fronds solitary or a few cohering temporarily, variously shaped, with 1 or 2 budding pouches (reproductive cavities) at or near the proximal end, usually marginal, in which viviparous daughter fronds develop continually
• Inflorescence spathaceous, in subfamily Lemnoideae 1 or 2 marginal cavities may occasionally produce an emergent inflorescence enclosed in a spathe which ruptures at anthesis; in subfamily Wolffioideae emergent inflorescences are formed in 1 or 2 special dorsal cavities (apart from budding marginal budding pouches), and lack a spathe
• Flowers unisexual, rarely produced, without perianth
• Male flowers reduced to 1 stamen; anther 1- or 2-thecous
• Female flower flask-shaped; ovary 1-locular, with 1-4 basal ovules; style short; stigma apical
• Fruit a 1-4-seeded utricle
• Seeds ribbed or smooth; embryo straight; endosperm fleshy or 0

Classification Notes:

• Family derived from Araceae (neotenous) and placed there by A.P.G. (1998)

Nomenclature:

• Lemnaceae
  • Brown: 39 (1897)
  • Friedrich-Holzhammer: 1 (1967)
  • Den Hartog & Van der Plas: 355 (1970)
  • Cook: 113 (1990)

Distribution & Notes:

• Global: Genera 4, species 29; widespread in still, fresh water, many are cosmopolitan
• Southern Africa: Genera 4, species 10

References:

• A.P.G. 1998. An ordinal classification for the families of flowering plants. Annals of the Missouri Botanical Garden 85
• BROWN, N.E. 1897. Lemnaceae. Flora capensis 7
• COOK, C.D.K. 1990. Aquatic plant book. SPB Academic Publishing, The Hague
• DEN HARTOG, C. & VAN DER PLAS, F. 1970. A synopsis of the Lemnaceae. Blumea 18
• FRIEDRICH-HOLZHAMMER, M. 1967. Lemnaceae. Prodromus einer Flora von Südwestafrika 163

Resources:

• Classification of Lemnaceae
• Key to Lemnaceae genera

• Lemnaceae genera: