Tweet this page Like this page Email this page Share this page Home» Resources » Identification » Identification of algae » Freshwater algae » How to identify algae » Identification guide » Colonial » Cell contents (chloroplasts when present) are green or blue-green Cell contents (chloroplasts when present) are green or blue-green 3. Do the cells contain organelles? Cells lack organelles (although vesicles may be present); cells generally small and blue-green (although may have secondary red pigment Cells contain membrane-bound organelles (chloroplasts, nuclei etc) and cell contents are grass green