Are they protists, plants, or a little of both? Draw your own conclusions after examining these five slides. Chlamydomonas and Volvox are flagellated protists often grouped with the green algae due to similarities in pigmentation and structure. Ulothrix is a true multicellular filamentous alga, and Ulva is a marine macro-alga that grows in sheets only two cells thick. A composite slide of six or more mixed green algae is included for practice with differentiation and identification.