Turtle-grass
Thalassia testudinum
Banks ex König
Description:
This sea grass has a horizontal rhizome, buried as much as 25 cm deep in the sediment. It gives rise to erect, green leaves. The leaves arise in clusters from short stalks; they are flat, 4-18 mm wide and may be 30 cm long. They are finely veined and rounded at the tips. The flowers are large, greenish white to pale pink and produce prominent seed pods that often wash ashore.
Habitat:
Turtle grass requires water of high salinity in areas sheltered from extreme wave action. It reaches depths of 20 m in clear water and can stand slight exposure to air at low tide levels. It requires a moderate depth of sediment for its rhizome network. Expansion of its beds occurs by lateral growth of the rhizomes at their ends. Except for the terminal part of the rhizome, they do not increase in length and if cut, they are incapable of rejoining. Hence destruction of the rhizomes by mechanical excavation leads to deep holes in the beds.
Many herbivorous fishes and green turtles Chelonia mydas feed heavily on turtle grass, and the primary production of this plant is important in tropical marine Atlantic ecosystems.
Distribution:
T. testudinum occurs throughout the Caribbean and the Gulf of Mexico. On the eastern coast of Florida it is not recorded north of Cape Canaveral.