Freshwater Algae Key

A1. Nonmotile algae without chloroplasts: Cyanobacteriophyta

A2. Motile algae with chloroplasts and flagella

B1. Motile single-cell algae

C1. Cells with one visible flagellum

C2. Cells with two equal length flagella

D1. Cells enclosed in firm, transparant, spherical mucilage

D2. Cells enclosed in rigid lorica

E1. Cells enclosed in a rough, reddish brown lorica; lorica separates along transverse (equatorial) groove: Hemitoma

E2. Cells circular in face view, lens-shaped in side view; enclosed in transparent or yellowish, granular lorica; lorica separated along longitudinal groove: Phacotus

D3. Cells not enclosed in lorica or surrounded by spherical or oval muicilage

C3. Cells with two dissimilar flagella

C4. Cells with more than two flagella

B2. Motile colonies with 4 or more cells

A3. Nonmotile algae with chloroplasts but without flagella

A4. Cells with paired, symmetric semi-cells: Desmids

A5. Cells enclosed in glassy, ornamental frustules: Diatoms