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 Microthamniales M. Melkonian, in L. Margulis et al., eds. (1990) Genus Microthamnion Nägeli, in Kützing (1849)