Gloeocapsa magma is blue-green algae, which is cyanobacteria, it is a type of algae. Algae are polyphyletic, an major algal groups are not all closely related to each other. Algae is NOT a taxonomic category, it is just a common name for all things photosynthetic that are NOT plants. Cyanobacteria are an ancient line of photosynthesizing bacteria, responsible for Oxygen gas in the atmosphere. It can be said that Cyanobacteria are responsible for all advanced forms (eukaryotic cells) of life on earth. It has gained notoriety in the Southeastern U.S. which is quickly spreading throughout the Midwest. The reason is this particular type of blue-green algae is responsible for creating the unattractive black roof stains and/or streaks commonly noticed by many. The blue-green algae, unicellular, accumulate over time; this accumulation begins to show the problematic black stains as the cyanobacteria develop their dark and hard UV-protective outer coating.