Light micrograph of red algae in the genus Batrachospermum. Members of this freshwater genus range in color from violet to blue-green and features long, branched, threadlike filaments with dense whorls of branchlets, resembling beads on a string. Spores are formed in clusters around the base of the carpogonium (female sex organ) after fertilization. Rheinberg illumination. Magnification: 5:1 at 35mm.