cryptic band names

Many green algae form long filaments. The cells stay attached after they divide. Some genera, like Spirogyra, Mougeotia and Zygnema can become so numerous they form dense mats of growth in surfaces of ponds, so-called pond scum. This pond scum is interesting for a study under the microscope. If you squeeze it in a jar you will collect many interesting organisms. And the filamentous algae are at least as interesting. The chloroplasts have distinct shapes. In Spirogyra the chloroplast runs through the cell like a helix. The image also shows the nucleus hanging on fine threads.