alga - primitive chlorophyll-containing mainly aquatic eukaryotic organisms lacking true stems and roots and leavesseaweed - plant growing in the sea, especially marine algae golden algae - algae having the pigments chlorophyll and carotene and xanthophyll yellow-green algae - any alga of the division Chrysophyta with its chlorophyll masked by yellow pigment diatom - microscopic unicellular marine or freshwater colonial alga having cell walls impregnated with silica confervoid algae - algae resembling confervae especially in having branching filaments brown algae - algae having the chlorophyll masked by brown and yellow pigments chlorophyte, green algae - algae that are clear green in color; often growing on wet ricks or damp wood or the surface of stagnant water red algae - marine algae in which the chlorophyll is masked by a red or purplish pigment; source of agar and carrageenan |