The Archaeplastida are a major line of eukaryotes, comprising the land plants, green and red algae, and a small group called the glaucophytes. All of these organisms have plastids surrounded by two membranes, suggesting they developed directly from an endosymbiotic cyanobacteria. In all other groups, plastids are surrounded by three or four membranes, and were acquired secondarily from green or red algae. Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Divisions Non-vascular plants (bryophytes) Hepaticophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants The embryophytes are the most familiar group... Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... Possible classes Florideophyceae Bangiophyceae Cyanidiophyceae The red algae (Rhodophyta, pronounced /ˈrəʊdə(ʊ)ˌfʌɪtə/) are a large group of mostly multicellular, marine algae, including many notable seaweeds. ... The glaucophytes, also referred to as glaucocystophytes or glaucocystids, are a tiny group of freshwater algae. ... Plastids are major organelles found only in plants and algae. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ...

The cells typically lack centrioles and have mitochondria with flat cristae. There is usually a cell wall including cellulose, and food is stored in the form of starch. However, these characters are also shared with other eukaryotes. The main evidence the Archaeplastida form a monophyletic group come from genetic studies, which indicate that plastids probably had a single origin. A centriole in biology is a barrel shaped microtubule structure found in most animal cells, and cells of fungi and algae though not frequently in plants. ... Mitochondria structure : 1) Inner membrane 2) Outer membrane 3) Crista 4) Matrix In cell biology, a mitochondrion (plural mitochondria) (from Greek mitos thread + khondrion granule) is an organelle found in most eukaryotic cells. ... A cell wall is a more or less solid layer surrounding a cell. ... Cellulose (C6H10O5)n is a long-chain polymer polysaccharide carbohydrate, of beta-glucose. ... Starch is a complex carbohydrate which is insoluble in water. ... In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ...

The archaeplastids fall in two main evolutionary lines. The red algae are pigmented with chlorophyll a and phycobilins, like most cyanobacteria. The green algae and land plants are pigmented with chlorophylls a and b but lack phycobilins. The positions of the glaucophytes are uncertain; they have the typical cyanobacterial pigments, and are unusual in retaining a cell wall within the plastids (called cyanelles). Chlorophyll is a green photosynthetic pigment found in plants, algae, and cyanobacteria. ... Phycobilins are the chromophores of phycobiliproteins (photosynthetic pigments) found in cyanobacteria and in the chloroplasts of red algae, glaucophytes and some cryptomonads (though not in green algae and higher plants). ...

Cavalier-Smith (1981) suggested that the kingdom Plantae should refer to this group, and accordingly it may be called the Plantae sensu lato, but this has not been generally adopted, partly because of questions over its monophyly. The more precise name Archaeplastida was introduced by Adl et al. (2005). Thomas Cavalier-Smith is a professor of evolutionary biology at the University of Oxford, and is winner of the International Prize for Biology 2004 and one of the most notable researchers concerning the relationships, development, and classification of living things. ... Divisions Green algae land plants (embryophytes) non-vascular embryophytes Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses vascular plants (tracheophytes) seedless vascular plants Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongue ferns seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering...

References

• T. Cavalier-Smith (1981). Eukaryote Kingdoms: Seven or Nine?. BioSystems 14: 461-481.
• Sina M. Adl et al (2005). The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists. Journal of Eukaryotic Microbiology 52 (5): 399. DOI:10.1111/j.1550-7408.2005.00053.x.