Description:

• Submerged annual or occasionally perennial herbs of fresh or brackish water, monoecious or dioecious, with leafy stems permanent or deciduous
• Roots adventitious, unbranched, appearing from an annular skinfold at rhizome nodes
• Rhizomes creeping, matted, bracteate
• Leaves alternate or opposite, often apparently distichous or 3(4) in pseudo-whorls (Zannichellia); plane of distichy often changing from parent to branch axis; leaves linear, 1- (or ± 3)-veined or reduced to membranous, biseriate scale leaves without vascular tissue, sometimes with fibres; foliage leaves in all genera, except Zannichellia, with a basal, membranous and sometimes fibrous, open but overwrapping sheath extended distally beyond insertion of blade as an auriculate ligule; apex rounded, pointed or sometimes truncate, 3-toothed, or dentate; those of upper fertile leaves modified into bracts with lamina reduced or wanting
• Flowers unisexual, solitary or in sympodial axillary clusters; 'perianth' 0 or present, flask-shaped or rarely of 3 small scales
• Male flowers with 2 (rarely 1 or 3) united anthers, 4-, 2- or 1-thecous (8-, 4- or 2-sporangiate), with an apical appendage and 1 or more longitudinal slits; filament (or pedicel) lengthening rapidly at anthesis; pollen globose or filamentous, pollination hydrophilous
• Female flowers: carpels 1, 3-5(-9), free; style long or short, simple; stigma capitate, peltate, funnel-shaped, or 2-4-lobed; ovule solitary, pendulous, anatropous, bitegmic
• Fruit a drupelet
• Seeds with cotyledon spirally coiled; endosperm 0

Nomenclature:

• Zannichelliaceae
  • Obermeyer: 73 (1966)
  • Cook: 222 (1990)

Distribution & Notes:

• Global: Genera 4, species ± 10, cosmopolitan
• Southern Africa: Genera 3, species 3-5

References:

• COOK, C.D.K. 1990. Aquatic plant book. SPB Academic Publishing, The Hague
• OBERMEYER, A.A. 1966. Zannichelliaceae. Flora of southern Africa 1

Resources:

• Key to Zannichelliaceae genera

• Zannichelliaceae genera: