The thallus is closely attached to the substrate (adnate) and built of small, warty to lobulate granular patches (areoles) that are dark brown to almost black. Apothecia (fruiting bodies) are rather small, the same colour as the thallus, and remain distinctly concave. The algal partner (photobiont) occurs in bead-like chains, and the tissue beneath the hymenium (the hypothecium) is colourless. Sterile filaments interspersed between the spore sacs (paraphyses) are clear with tawny tips. Asci are somewhat cylindrical and inflated, producing four large, oblong ascospores that are muriform—divided by several transverse and longitudinal septa—with three more strongly marked cross-walls. The spores are constricted at the septa and blunt at both ends, measuring 22–34 × 10–16 μm. The hymenial gel stains an intense blue with iodine. Asexual propagules (conidia) are linear, straight or very slightly curved, about 3–4 μm long and roughly four times longer than wide.[3]
