You can browse though the hierarchy by clicking on the names below and drilling down. At each level the numbers of current species are given for each taxon. Only currently accepted names are currently included. Fossils are also currently included but only marginally affect the numbers.
What is included in "The Algae"?
Algae are best defined as "oxygenic photosynthesisers other than embryophyte land plants" (Cavalier-Smith European Journal of Protistology 56: 255, 2016). In general, we have used botanical endings for phyla, classes, orders and families (-phyta, -phyceae, -ales, -aceae) where the organisms conform with this definition and zoological endings (-zoa, -ea, -ida,- idae) where they do not. Of course, one might ask why include these supposed animals at all? The answer is generally that these organisms were or are treated by some as algae. This is particularly apparent in the flagellate groups, particularly the euglenoid flagellates.
For the marine flowering plants we follow Angiosperm Phylogeny Group III system in respect of the Angiosperms in which all seagrasses are in one order, the Alismatales. The family Cymodoceaceae is not recognised currently in this system, but we have retained it for the present. The 76 included seagrasses are, of course, not algae, but are included here for the convenience of marine phycologists.
Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
You can search for a particular taxon (e.g. "Zygnematales"; "Zygnemataceae"; "Zygnema") at any level by entering the exact name in the field opposite.