Usually dichotomous up to several orders, with occasional fine laterals extending from the blades to give the appearance of being bushy, and multipartite at sites of injury. Branches often, becoming more dense in the upper sections of the plant. Rises alone from a discoid holdfast, thallus erect. Axes truncated, nearly cartilaginous; basal branches constricted at base. Up to 15 cm long and 4 mm wide linear blades with typically obtuse, acute apices on finer branches. The blade’s edges and surface are smooth. Dried specimens are black to green; fresh examples are purple to green and hard but malleable. Mature blades frequently have large galls or tumors visible on their surface. The plants range in color from grass green to deep purple.