Anisomeridium globosum is a species of corticolous (bark-dwelling), crustose lichen in the family Monoblastiaceae. This species is characterised by its greyish-green thallus and its almost (spherical) ascomata (fruiting bodies). The are 1-septate, meaning they are divided into two sections, and measure 8âÂÂ10.5 üm by 4.5âÂÂ6 üm. The septum (dividing wall) is distinctly submedian, such that the lower cell is only about a quarter of the size of the upper cell.
The type specimen of Anisomeridium globosum was collected from the do Junco in Capela, Sergipe, Brazil, at an elevation of about . The thallus is thin, shiny, and greyish-green, surrounded by an irregular white (a border around the thallus) about 1 mm wide. The ascomata are almost (more or less spherical), 0.3âÂÂ0.45 mm in diameter, and superficial (situated on the surface) in the bark but completely covered by a thin layer of thallus. The walls of the ascomata are (blackened) all around. The ostioles (openings) are apical (at the top), black, and protrude through the thallus. The , the tissue between the asci, does not contain oil droplets, and its filaments interconnect above the asci. The asci are cylindrical, measuring 80âÂÂ95 üm by 5.5âÂÂ7.5 üm, and have a small ocular chamber. The ascospores are hyaline (translucent), (arranged in a single row), with a pointed lower end and a rounded upper end. Pycnidia (small asexual fruiting bodies) have not been observed. Chemically, the thallus does not fluoresce under ultraviolet light, and no substances were detected using thin-layer chromatography.
Anisomeridium globosum is found on smooth bark in undisturbed Atlantic rainforests and is only known to occur in Brazil. This species is notable within its genus for having a (having a cortex or outer layer) thallus, which is relatively rare. Other species with a corticate thallus tend to have larger ascospores and differ in other key characteristics.