Algae
In the strictest sense, any of several otherwise unrelated Terragen organisms that are capable of photosynthesis but have a simpler organization than plants. Unlike plants they do not develop from embryos and do not produce complex organs. They may be single-celled or multicellular, and they are typically aquatic to semi-aquatic although a few live in moist terrestrial environments. Similar xenobiological organisms may also be called algae, and so may simple solar-powered and neumann-capable nanotech bots (see nanoalgae).