This foliose lichen grows closely attached to substrate surface. It has long, flat lobes with irregular divisions along the margins. The lobe tips are inflated and bulbous, and covered in minute cilia. The upper surface is smooth or slightly wrinkled, pale green-gray or gray, and shiny. It has dense, cylindrical isidia. The lower surface is pale to dark brown, with concolorous rhizines. Apothecia are rare, and when present, have an isidiate margin and a red-brown to dark brown disc. B. isidzia grows on tree bark in open tropical and subtropical areas of the world.