Pflanzenreich Haeckel (1866) - plants
   Division Euthallophyta
     Subdivision Euphyceae
       Class Chlorophyceae Wille (1884) - chlorophytes
         Series Protococcales see Order Protococcales
           1 Family Volvocaceae Ehrenb. (1834)
           2 Family Tetrasporaceae Wittr. (1872), nom. cons.
           3 Family Chlorosphaeraceae
           4 Family Pleurococcaceae see Family Chaetophoraceae Grev.
           5 Family Protococcaceae see Family Ctenocladaceae
           6 Family Hydrodictyaceae Dumort.