Description:

• Submerged, dioecious, perennial marine plants
• Rhizomes creeping, either herbaceous, monopodial and rooting at nodes or ligneous, sympodial and rooting from internodes
• Leaves alternate, distichous, or apparently opposite, scale-like on rhizomes, ribbon-like on branches, with 3-several parallel or pseudoparallel nerves, with an open basal sheath and ligule at its junction with the blade, truncate or emarginate at apex; sheath perhaps stipular
• Flowers unisexual, small, solitary, terminal on short side branches; water-pollinated; sepals and petals 0
• Male flowers subsessile or stalked, consisting of two 2-thecous, longitudinally dehiscent anthers, paired on a common filament; connectives usually prolonged; pollen grains often released in water, becoming filamentous
• Female flowers sessile or stalked, each consisting of 2 mutually free carpels; style either long (Halodule) or short, simple or divided into 2-4 strap-shaped stigmata; ovule solitary, pendulous, orthotropous, bitegmic
• Fruit indehiscent, either with stony endocarp (Halodule) or viviparous (Thalassodendron)
• Seeds pendulous; endosperm 0

Nomenclature:

• Cymodoceaceae
  • Obermeyer: 73 (1966) under Zannichelliaceae
  • Den Hartog: 144 (1970)
  • Dahlgren et al.: 320 (1985)
  • Cook: 63 (1990)

Distribution & Notes:

• Global: Genera 5, species 16, distributed in the tropical seas, some extending into subtropical and warm temperate waters. The genus Amphibolis is limited to the Australian temperate waters
• Southern Africa: Genera 2, species 2, along the eastern coast

References:

• COOK, C.D.K. 1990. Aquatic plant book. SPB Academic Publishing, The Hague
• DAHLGREN, R.M.T., CLIFFORD, H.T. & YEO, P.F. 1985. The families of the monocotyledons. Springer-Verlag, Berlin
• DEN HARTOG, C. 1970. The seagrasses of the world. North-Holland Publishing Company, Amsterdam
• OBERMEYER, A.A. 1966. Zannichelliaceae. Flora of southern Africa 1

Resources:

• Key to Cymodoceaceae genera

• Cymodoceaceae genera: