Soft-Bodied Stream Algae of California


Key to Algal Phyla/Classes

1. Cells without chloroplasts, pigmentation blue-green, gray-green, yellowish, violet distributed in most of the cytoplasm Cyanobacteria

1. Cells with chloroplasts where pigments are located of various dominant colors



2. Storage products starch which stain reddish, purple to black with Lugol’s solution 3

2. Storage products different than starch and do not stain positively with Lugol’s solution




3. Chloroplasts light to dark green with starch inside Chlorophyta

3. Cells with starch in the cytoplasm outside of the chloroplast



4. Cells non-motile, bluish or red; thallus coccoid, filamentous, or tissue-like Rhodophyta

4. Cells motile



5. Cells usually red or blue, unicellular flagellates, often bean-shaped, commonly dorsiventrally flattened with two or more unequal subapical flagella Cryptophyta

5. Cells mostly yellow-brown, olive-brown, rarely bluish or reddish; unicellular flagellates (rarely coccoid or filamentous) having two unequal flagella, one transverse and encircling the cell, and the other directed posteriorly



6. Greenish unicellular flagellates with a long flagellum emerging from an apical depression, cells with pellicle and may be surrounded by lorica, chloroplasts two to several Euglenophyta

6. Cells greenish or golden to brown, with no pellicle or apical depression




7. Greenish unicells to colonies, filaments or coenocytes Xanthophyceae

7. Golden-colored to brown




8. Unicells, flagellates to colonies Chrysophyceae

8. Cells covered with scales or filamentous




9. Golden-colored flagellates to colonies; cells covered with silica scales Synurophyceae

9. Branched filaments




10. Golden-colored cells Phaeothamniophyceae

10. Brown-colored cells