Chaetomorpha, a macroalgae, is classified under the Plantae kingdom. They use to think that all algae were plants because it green (mostly) and it's photosynthetic. But evidently micro algae doesn't have the same cell structure as plants--no cellular wall, etc... . They are in fact considered protists, (I'm fairly sure, but correct me if I'm wrong). So, is macro a plant, and micro a protist? plz clarify! Then there are things like cyanobacteria that looks like algae, which I think is a moneran/Prokaryote. But maybe it's not a bacteria at all but some sort of protazoa? Had a lot of conflicting research. Just curious. Anyone know about this stuff? Oh, for that matter, anyone familiar with "moss balls" (lotta folks have them in freshwater planted aquaria)? Is moss a macroalgae?