Phacus is a genus of photosynthetic microalgae, in the phylum Euglenozoa. These free-swimming protists are generally flat and leaf shaped, appearing delicate as they whip their flagella to move through their environment.

I collected a sample from one of my nearby collection sites, planters at a local playground. One of the planters has provided me with several blooms of different organisms this summer, and this current sample was no exception. The very first slide I made was covered edge to edge with Phacus. There are at least two species on display in the video and images.