Thallus often long (up to 2 m or more); pale greenish. Hanging freely, with one long main branch and many short, perpendicular side branches, all cylindrical. Surface often with circular cracks and white patches. On conifers and hardwoods in humid and open forest habitats within a few miles of salt water. Sensitive to air pollution, especially sulfur dioxide and acid rain. At least fifteen species of Usnea occur in this region.