TETRASPORA, CHLOROSACCUS, AND PHAEOSPHAERA , A UNIQUE EXAMPLE OF PARALLEL EVOLUTION IN THE ALGAE 1

SUMMARY The similarity among Tetraspora, Chlorosaccus, and Phaeosphaera, belonging to the Chlorophyceae, Xanlhophyceae, and, Chrysophyceae, adds to the concept of parallel evolution among algal classes. Not only are all 3 genera characterized by colonial organization, nonmotile vegetative cells embedded in a gelatinous matrix, but the genera are also found in the same habitat. Further, the characteristic pseudocilia of Tetraspora cells are also found in colonics of Phaeosphaera. Morphological features of pseudocilia of Tetraspora and the nature of papillae in Chlorosaccus are also presented.