|An assortment of thallophyte Viridiplantae in a rock pool, Taiwan|
|Scientific classification |
- Plantae Copeland, 1938, 1956
- Euchlorophyta Whittaker, 1969
- Chlorophyta sensu van den Hoek & Jahns, 1978
- Chlorobionta Jeffrey 1982, emend. Bremer 1985, emend. Lewis and McCourt 2004
- Chlorobiota Kendrick and Crane 1997
- Chloroplastida Adl et al., 2005
- Viridiplantae Cavalier-Smith 1981
- Phyta Barkley 1939 emed. Holt & Uidica 2007
- Cormophyta Endlicher, 1836
- Cormobionta Rothmaler, 1948
- Euplanta Barkley, 1949
- Telomobionta Takhtajan, 1964
- Embryobionta Cronquist et al., 1966
- Metaphyta Whittaker, 1969
Viridiplantae (literally "green plants") are a clade of eukaryotic organisms made up of the green algae, which are primarily aquatic, and the land plants (embryophytes), which emerged within them. Green algae traditionally excludes the land plants, rendering them a paraphyletic group. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them. They have cells with cellulose in their cell walls, and primary chloroplasts derived from endosymbiosis with cyanobacteria that contain chlorophylls a and b and lack phycobilins. More than 350,000 species of Viridiplantae exist.
In some classification systems, the group has been treated as a kingdom, under various names, e.g. Viridiplantae, Chlorobionta, or simply Plantae, the latter expanding the traditional plant kingdom to include the green algae. Adl et al., who produced a classification for all eukaryotes in 2005, introduced the name Chloroplastida for this group, reflecting the group having primary chloroplasts with green chlorophyll. They rejected the name Viridiplantae on the grounds that some of the species are not plants, as understood traditionally. The Viridiplantae are made up of two clades: Chlorophyta and Streptophyta as well as the basal Mesostigmatophyceae and Chlorokybophyceae. Together with Rhodophyta and glaucophytes, Viridiplantae are thought to belong to a larger clade called Archaeplastida or Primoplantae.
A taxonomic evaluation of eukaryotes based on myosin distribution showed the Viridiplantae lost class-I myosins.