AlgaeBase offers a free database of information on algae species around the world. This project is part of the Species 2000 initiative, created to enumerate "all known species of plants, animals, fungi and microbes on...

This seven-page guide can be used to identify freshwater microorganisms. Categories include microscopic autotrophic organisms (i.e. algae), heterotrophic protozoa, other freshwater plankton (Animalia, Monera, etc), and...

Protist Image Data (PID) is an online database that provides pictures and short descriptions of selected Protist genera, especially those genera whose species are frequently used as experimental organisms or are...

Housed at the University of Texas-Austin, The Culture Collection of Algae "includes over 2,300 different strains of living algae, representing most major algal taxa." Site visitors will find an online catalogue of...