A1. NONMOTILE ALGAE WITHOUT CHLOROPLASTS: CYANOBACTERIA

B2. VEGETATIVE CELLS UNITED INTO COLONIES

C3. CELLS ARRANGED IN SPHERICAL OR NEARLY SPHERICAL COLONIES

D2. CELLS NOT ATTACHED TO RADIATING MUCILAGE STRANDS (STRANDS MAY BE PRESENT BUT INVISIBLE UNDER NORMAL MAGNIFICATION)

E2. CELLS GRAY OR BLUE-GREEN (NOT MOTTLED BROWN) WHEN VIEWED UNDER THE MICROSCOPE

F1. CELLS TINY (width <2 µm), ROD-SHAPED, PALE BLUE-GRAY; FORMING SHORT PSEUDOFILAMENTS INSIDE COLONY; COLONIES SPHERICAL, IRREGULAR, OR NET-LIKE (CLATHRATE): Cyanodictyon

F2. CELLS TINY (<4 µm), SPHERICAL OR OVAL; BLUE-GRAY, IN SINGLE FLAT LAYER FORMING SPHERICAL, IRREGULAR, OR NET-LIKE (CLATHRATE) COLONIES: Pannus

F3. CELL WIDTH ≥3 µm; SPHERICAL OR BROADLY OVAL, BRIGHT BLUE-GREEN; ARRANGED IN SINGLE LAYER AROUND HOLLOW COLONY CENTER; COLONIES SPHERICAL: Coelosphaerium and Coelomoron

F4. CELLS SPHERICAL, OVAL, OR ELLIPTICAL, BLUE-GRAY, GRAY, GREEN, OR BROWNISH; LOOSELY DISTRIBUTED IN AMORPHOUS OR SPHERICAL COLONIES, USUALLY SURROUNDED BY DIFFUSE MUCILAGE: Aphanocapsa and Aphanothece

F5. CELLS NARROWLY ELLIPTICAL, CYLINDRICAL, OR FUSIFORM; COLONIES COMPACT, SURROUNDED BY BROAD MUCILAGE: Rhabdogloea