sea moss

(noun) sessile aquatic animal forming mossy colonies of small polyps each having a curved or circular ridge bearing tentacles; attach to stones or seaweed and reproduce by budding. Synonyms: bryozoan, polyzoan, sea mat, sea moss, moss animal.

(noun) any of various red algae having graceful rose to purple fronds (e.g. dulse or carrageen). Synonyms: sea moss.