duke: a British peer of the highest rank
peer: a nobleman (duke or marquis or earl or viscount or baron) who is a member of the British peerage
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