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)

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

C1. CELLS ATTACHED TO ZOOPLANKTON (EPIZOIC) OR LIVING INSIDE ZOOPLANKTON OR OTHER AQUATIC ANIMALS (ENDOZOIC)

D1. CELLS CRESCENT-SHAPED (GENTLY CURVED) WITH STOUT APICAL AND POSTERIOR SPINES; USUALLY EPIZOIC, OFTEN ON DAPHNIA: Korshikoviella

D2. CELLS RESEMBLE EUGLENA BUT ARE USUALLY EPIZOIC ON FRESHWATER MICROCRUSTACEANS: Colacium

D3. CHLORELLA-LIKE CELLS LIVING INSIDE ZOOPLANKTON AND OTHER AQUATIC ANIMALS (ENDOZOIC): Zoochlorella group

C2. CELLS SOLITARY, ATTACHED TO AQUATIC PLANTS (EPIPHYTIC)

C3. CELLS FORMING COLONIES; ATTACHED TO PLANTS (EPIPHYTIC)

C4. CELLS JOINED OR POSITIONED END-TO-END IN FILAMENTS OR PSEUDOFILAMENTS; FILAMENTS 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)