chlorophyta: large division of chiefly freshwater eukaryotic algae that possess chlorophyll a and b, store food as starch, and cellulose cell walls; classes Chlorophyceae, Ulvophyceae, and Charophyceae; obviously ancestral to land plants
division: (biology) a group of organisms forming a subdivision of a larger category
great-nephew: a son of your niece or nephew