In the old scheme of classification, i.e. the five kingdom scheme, Protista is a kingdom comprised of animal-like (protozoa), plant-like (algae), and fungus-like (slime molds and water molds) organisms. Accordingly, Protista is divided into several phyla. The plant-like or algal species are further divided into the following phyla: Euglenophyta, Chrysophyta (diatoms), Pyrrophyta (dinoflagellates), Chlorophyta (green algae), Phaeophyta (brown algae), and Rhodophyta (red algae).1 Recent studies and findings, though, would lead to changes in the taxonomic positions and to newer systems of classification.2 According to the Encyclopedia of Life, Rhodophyta has the following taxonomic orders: Bangiophyceae, Compsopogonophyceae, Cyanidiophyceae, Florideophyceae, Porphyridiophyceae, Rhodellophyceae, and Stylonematophyceae.
Rhodophyta is a clade comprised of red algal species. As their name implies, the red algae are algal species that appear reddish in color. That is because of their accessory pigments, phycoerythrin, phycocyanin and allophycocyanins. They also have chlorophyll pigments. Another distinctive feature of red algae is the absence of flagella and centrioles. Many of them are marine species and are found along the coastal and continental shelf areas of tropical, temperate and cold-water regions.3
Word origin: rhodo- (“red”) + -ophyta
1 Pascher, A. (1914). "Über Flagellaten und Algen ". Berichte der deutsche botanischen Gesellschaft 32: 136–160.
2 The NCBI taxonomy database. Retrieved from .
3 Rhodophyta. Retrieved from [].