Codium

a genus of marine green algae of the class Siphoneae. The thallus is spherical, cushion-shaped or fruticose, 5–50 cm high, and consists of slender, interwoven threads that end in a layer of large, elongated sacs containing chloroplasts. Reproduction is by heterogamy, and meiosis occurs in gametangia. All species of Codium live in warm and temperate seas.