Here is a list of the various divisions that have been identified in microbiotic crusts collected in the Western U.S.  These links consist of species descriptions and pictures.

                    These divisions will have a brief description and representative picture

Blue Green Algae (Cyanobacteria)

Green Algae (Chlorophyta)

Diatoms (Bacillariophyta)

Yellow-Green Algae (Xanthophyta)

Eustigmatophytes (Eustigmatophyta)