Freshwater Algae Key

A1. NONMOTILE ALGAE WITHOUT CHLOROPLASTS: CYANOBACTERIA

A2. NONMOTILE ALGAE WITH CHLOROPLASTS

B1. CELLS USUALLY SOLITARY

B2. NONMOTILE COLONIES WITH TWO OR MORE CELLS

B3. FILAMENTOUS ALGAE (INCLUDING PSEUDOFILAMENTS)

C1. FILAMENTS OR PSEUDOFILAMENTS ATTACHED TO AQUATIC PLANTS (EPIPHYTIC)

C2. CELLS FORM PSEUDOFILAMENTS WHERE THEY ARE ALIGNED END-TO-END BUT NOT JOINED ACROSS THE ENDWALL

D1. PSEUDOFILAMENTS ARE ENCLOSED IN A VISIBLE MUCILAGE LAYER OR CELLS ARE FORMED AT THE END OF MUCILAGE TUBES

E1. PSEUDOFILAMENTS MOSTLY UNBRANCHED

E2. PSEUDOFILAMENTS SPARSELY OR DENSELY BRANCHED

D2. PSEUDOFILAMENTS ARE NOT ENCLOSED IN DISTINCT MUCILAGE

C3. UNBRANCHED FILAMENTOUS ALGAE

C4. BRANCHED FILAMENTOUS ALGAE

B4. CELLS ATTACHED TO ZOOPLANKTON (EPIZOIC), LIVING INSIDE ZOOPLANKTON OR OTHER AQUATIC ANIMALS (ENDOZOIC), OR ATTACHED TO AQUATIC PLANTS (EPIPHYTIC)

A3. MOTILE ALGAE WITH CHLOROPLASTS AND FLAGELLA

A4. CELLS DIVIDED INTO MIRROR-IMAGE SEMI-CELLS: Desmids (see key at cedar.wwu.edu/cedarbooks/14/ )

A5. CELLS ENCLOSED IN GLASSY, ORNAMENTAL FRUSTULES: Diatoms (see key at diatoms.org)