Pithophora belongs to the family of filamentous green algae. It may be found growing on the bottom or in dense mats on the surface of ponds. This algae is often described as resembling a tangled mass of cotton or wool-like growth which is very course to the touch. It may range in color from lime green to a dark greenish brown. The surface mats generally form in warmer weather when gas bubbles, produced by the plant, are trapped within the dense algal growth, causing them to become buoyant. Disturbance of these mats by high wind or heavy rain events may cause them to temporarily sink to the bottom. This often gives a false impression that the growth has "disappeared", only to have it return to the surface within several days.