Freshwater Algae Key

A1. NONMOTILE ALGAE WITHOUT CHLOROPLASTS: CYANOBACTERIA

A2. NONMOTILE ALGAE WITH CHLOROPLASTS

A3. MOTILE ALGAE WITH CHLOROPLASTS AND FLAGELLA

B1. MOTILE COLONIES WITH TWO OR MORE CELLS

B2. MOTILE SINGLE-CELL ALGAE

C1. CELLS WITH ONE VISIBLE FLAGELLUM

C2. CELLS WITH TWO EQUAL LENGTH FLAGELLA

C3. CELLS WITH TWO DISSIMILAR FLAGELLA

D1. CELLS WITH ONE FORWARD AND ONE TRAILING FLAGELLUM

E1. CELLS TEARDROP-SHAPED OR OVAL; CELL WALL CONTAINS MANY SCATTERED TRICHOCYSTS: Gonyostomum

E2. CELLS OVAL OR SPHERICAL; CELL WALL CONTAINS KNOBBY MUCILAGE GRANULES (NO TRICHOCYSTS): Vacuolaria

D2. CELLS WITH ONE TRANSVERSE AND ONE TRAILING FLAGELLUM (Dinoflagellates)

D3. CELLS WITH TWO FORWARD-DIRECTED APICAL OR SUBAPICAL FLAGELLA

C4. CELLS WITH MORE THAN TWO 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)