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)

D1. CELLS WITH LONG HAIR-LIKE SETAE

D2. CELLS LACKING OR MOSTLY LACKING LONG HAIR-LIKE SETAE

E1. CELLS SPHERICAL; FORMING LOOSELY ARRANGED PSEUDOFILAMENTS AT THE ENDS OF UPRIGHT, HIGHLY BRANCHED MUCILAGE TUBES: Mischococcus

E2. CELLS CLUB-SHAPED OR ELLIPTICAL, GOLDEN BROWN; FILAMENTS UPRIGHT AND HIGHLY BRANCHED: Phaeothamnion

E3. CELLS RECTANGULAR, GOLDEN BROWN; FORMING IRREGULAR, RECTANGULAR COLONIES OR SHORT FILAMENTS; EPIPHYTIC ON FILAMENTOUS ALGAE: Phaeoplaca

E4. CELLS RECTANGULAR, BRIGHT GREEN; JOINED INTO LONG FILAMENTS RADIATING FROM CENTRAL POINT TO FORM FLAT, SPHERICAL OR OVAL COLONY: Coleochaete

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

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)