Thallus dimorphic consisting of small, often insignificant or evanescent basal squamules or granules from which pseudopodetia arise. Pseudopodetia erect, branching, variously perforate, dying at base and proliferating apically, without squamules, rather brittle and fragile when dry, flaccid when wet, perforations in some species forming distinctive clathrate-fenestrate patterns. Photobiont green . Medulla scarcely developed, arachnoid chondroid layer absent, its function taken by the cortex which is composed of conglutinate, longitudinal hyphae. Apothecia minute, on the apices of short terminal branches, often aggregated, peltate, disc plane, margin disappearing. Ascospores simple, long-ellipsoid to subfusiform, 8 per ascus. Pycnidia terminal on smaller branches of sterile pseudopodetia. Conidia, colourless, curved.