1.sea-lettuce family - thin flat or tubular green algae family Ulvaceae, Ulvaceaeprotoctist family - any of the families of Protoctistaorder Ulvales, Ulvales - an order of protoctistgenus Ulva, Ulva - type genus of the family Ulvaceae; green seaweed having a thallus two cells thick: sea lettuce
sea-lettuce family - thin flat or tubular green algae