Description:

• Submerged, annual or perennial herbs, growing attached to rocks in swift-flowing freshwater, especially rapids or waterfalls; often resembling mosses, liverworts or algae; all vegetative parts of plant chlorophyllous; plant base a polymorphous dorsiventral thallus giving rise to haptera (flattened organs adhering to substrate by a cement-like substance) and to stems and flowering shoots
• Stems simple or with short branches, leafless to densely leafy, or reduced and present only in flowering and/or well-developed plants
• Leaves often linear to filiform and floating, entire or divided, and/or small, moss-like, or reduced and bract-like; stipules 0 or tooth-like
• Flowers bisexual, regular or irregular, small, solitary or cymose; spathella (closed membranous sac enclosing flower bud and bursting irregularly at anthesis) persistent or 0
• Perianth with 2, 3 or 0 segments, free or connate at base
• Stamens 1 or 2, hypogynous; filaments free or ± connate; anthers 2-thecous, opening lengthwise; pollen grains in diads or monads
• Ovary superior, 1-3-locular; placenta central, swollen, multi-ovulate; septa thin; styles 2 or 3, basally ± fused
• Fruit a septicidal, often ribbed capsule
• Seeds many, minute; endosperm 0; epidermis becoming mucilaginous when moistened

Nomenclature:

• Podostemaceae
  • Hill: 482 (1912)
  • Podlech: 62 (1966)
  • Obermeyer: 205 (1970)
  • Aston: 1 (1990)
  • Cook: 175 (1990)
  • Philbrick & Novelo: 210 (1995)
  • Cusset: 1 (1997)

Distribution & Notes:

• Global: Genera ± 51; species ± 268 (including Tristichaceae); widely distributed throughout the tropics and subtropics of Old and New World
• Southern Africa: Genera 4, species 4
  • Most of the species are endemic to a small geographical area, some confined to a single river

References:

• ASTON, H.I. 1990. Podostemaceae. Flora of Australia 18
• COOK, C.D.K. 1990. Aquatic plant book. SPB Academic Publishing, The Hague
• CUSSET, C. 1997. Podostemaceae. Flora zambesiaca 9,2
• HILL, A.W. 1912. Podostemaceae. Flora capensis 5,1
• OBERMEYER, A.A. 1970. Podostemaceae. Flora of southern Africa 13
• PHILBRICK, C.T. & NOVELO A.R. 1995. New world Podostemaceae: Ecological and evolutionary enigmas. Brittonia 47,2
• PODLECH, D. 1966. Podostemaceae. Prodromus einer Flora von Südwestafrika 62

Resources:

• Key to Podostemaceae genera

• Podostemaceae genera: