Viridiplantae Cavalier-Smith, 1981 - green plants see Subkingdom Viridiplantae Caval.-Sm. (1981)
   Chlorophyta Pascher (1914) - green algae
     core chlorophytes
       Class Trebouxiophyceae T. Friedl (1995) - trebouxiophytes
         Genus Picochlorum W.J. Henley, J.L. Hironaka, L. Guillou, M.A. Buchheim, J.A. Buchheim, M.W. Fawley & K.P. Fawley (2004)