Thin flat or tubular green algae WordNet 3.0 & Open English WordNet

Ulvaceae is a widely distributed family of thin green algae having either a flat or a hollow tubular thallus, reproducing by the conjugation of planogametes or of zoospores, and being classed among the Ulotrichales or now more commonly placed in the order Ulvales. Wikipedia

Family of algae Wikidata