What is "thalassia testudinum"

Turtle \Tur"tle\, n. [Probably the same word as the word preceding, and substituted (probably by sailors) for the Spanish or Portuguese name; cf. Sp. tortuga tortoise, turtle, Pg. tartaruga, also F. tortue, and E. tortoise.]

1. (Zo["o]l.) Any one of the numerous species of Testudinata, especially a sea turtle, or chelonian.

   Note: In the United States the land and fresh-water tortoises are also called turtles.

2. (Printing) The curved plate in which the form is held in a type-revolving cylinder press.

   Alligator turtle, Box turtle, etc. See under Alligator, Box, etc.

   green turtle (Zo["o]l.), a marine turtle of the genus Chelonia, having usually a smooth greenish or olive-colored shell. It is highly valued for the delicacy of its flesh, which is used especially for turtle soup. Two distinct species or varieties are known; one of which ( Chelonia Midas) inhabits the warm part of the Atlantic Ocean, and sometimes weighs eight hundred pounds or more; the other ( Chelonia virgata) inhabits the Pacific Ocean. Both species are similar in habits and feed principally on seaweed and other marine plants, especially the turtle grass.

   Turtle cowrie (Zo["o]l.), a large, handsome cowrie ( Cypr[ae]a testudinaria); the turtle-shell; so called because of its fancied resemblance to a tortoise in color and form.

   Turtle grass (Bot.), a marine plant ( Thalassia testudinum) with grasslike leaves, common about the West Indies.

   Turtle shell, tortoise shell. See under Tortoise.

Thalassia testudinum, commonly known as turtlegrass, is a species of marine seagrass. It forms meadows in shallow sandy or muddy locations in the Caribbean Sea and the Gulf of Mexico.