Key to Common Algae Taxa Groups in the Phoenix
Area Water Supply System


1

 Cells possess chloroplasts; pigments usually yellow-green to golden-brown contained within 1 or more organelles (chloroplasts); cell walls siliceous (glass); cell wall observed as 2 overlapping halves (valves); food storage as oil and test negative for starch with iodine test; usually unicellular, but some form filaments (chains); some exhibit motility through a gliding motion, but flagella are absent; primarily reproduce asexually.

Bacillariophyceae
or
Diatoms

 2
Cells lacking chloroplasts; pigments are blue-green, purplish or olive-green and distributed throughout the cell; possess thin cell walls usually protected by mucilaginous sheath; lack distinct nucleus; lack motile cells; lack sexual reproduction; test negative for starch with iodine test.
Cyanophyta
(Cyanobacteria)
or
Blue-Green Algae


 3

 Cells possess chloroplasts; pigments usually grass-green and contained within 1 or more organelles (chloroplasts); distinct cell walls usually present; nucleus present; motile cells with 2-4 flagella; unicellular, colonial or filamentous organisms; possess sexual reproduction; usually possess 1 distinct pyrenoid that will test positive for starch with iodine test.

Chlorophyta
or
Green Algae