Light micrograph of a branching colony of the golden- brown alga Dinobryon sp.. The colony is composed of single-celled algae, each of which secretes a fine, transparent, cellulose sheath known as a lorica. Only the tips of the branches of the colony are inhabited; the bases are composed of old, abandoned sheaths. The cells are attached to the inside of the lorica by a contractile stalk. They possess two chloroplasts, two contractile vacuoles, an eyespot and two different types of flagellum. Various unidentified filamentous algae are also visible in the image. Magnification: x200 at 35mm size.