Ulvellaceae is a family of green algae in the order Ulvales.

Ulvellaceae consists of macroscopic and macroscopic algae that are usually attached to a substrate, occasionally free-living. They form branched filaments or pseudoparenchymatous masses. Cells contain a single nucleus and a single parietal chloroplast with one to several pyrenoids. Both asexual and sexual reproduction have been observed in representatives of Ulvellaceae.

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