Protista

The Kingdom Protista (one of the five kingdoms in Linnaean Taxonomy) includes all the Eukaryotes except for the Plantae, Fungi, and Animalia. A few forms are multicellular, ie the Phaeophyta (brown algae) and Rhodophyta (red algae). The vast majority, though, are single-celled and are typically only 0.01-0.5 mm in size, too small to be seen without a microscope. Protists are ubiquitous throughout aqueous environments and the soil, commonly surviving dry periods in the form of cysts; a few are important parasites.

Traditionally protists have been divided into:

Plant-like forms that have chloroplasts, the Algae;
Fungus-like forms, the Slime molds and Oomycota;
Animal-lie forms, the Protozoa, generally divided on the basis of morphology and locomotion into:

Except for the ciliates and Oomycota, these are all polyphyletic and frequently overlapping. More recently protists have been divided into more genuine groups on the basis of ultrastructural and chemical features. Aside from basal forms, these can be assorted into a few broad categories on the basis of the the form of the mitochondria and in particular the cristae within them.

There are several ways of breaking the group up into phyla, and most are heavily inadequates. One of the most recent schema:

Phylum Caryoblastea = Pelobionta

Phylum Rhizopoda (lobose and filose Amoeboids)

Phylum Granuloreticulosa

Phylum Actinopoda (actinopod Amoeboids)

Phylum Zoomastigina (heterotrophic Flagellates)

Phylum Euglenophyta

Phylum Cryptophyta

Phylum Haptophyta = Prymnesiophyta

Phylum Pyrrophyta = Dinoflagellata

Phylum Chrysophyta (basal Stramenopiles)

Phylum Xanthophyta

Phylum Eustigmatophyta

Phylum Bacillariophyta = Diatomophyta

Phylum Phaeophyta

Phylum Chlorophyta (basal Plantae)

Phylum Myxozoa = Cnidosporidia

Phylum Apicomplexa

Phylum Ciliophora

Phylum Myxomycota

Phylum Acrasiomycota (cellular Slime molds)

Phylum Labyrinthulomycota = Labyrinthulida

Phylum Plasmodiophoromycota = Plasmodiophorida

Phylum Hyphochytridiomycota

Phylum Oomycota