: Likely Blue-Green Algae ( Cyanobacteria ). They contain phycocyanin. Note: Some like Nostoc form firm, jelly-like "freshwater grapes" attached to rocks.
: For student projects, a dichotomous key helps identify algae by asking a series of "yes or no" questions about its features. Algae Corner: How to Identify Different Algae Types Easy identification of freshwater algae
: These look like hair-like strands or tangled mats. Spirogyra often feels slick and slimy. Pithophora feels "cottony" and coarse. : Likely Blue-Green Algae ( Cyanobacteria )