Herpothallon subglobosum is a species of corticolous (bark-dwelling), crustose lichen in the family Arthoniaceae. Found in China, it was formally described as a new species in 2022 by Pengfei Chen and Lulu Zhang. The type was collected in Baimaluo (Weixi County, Yunnan) at an elevation of 2100m (6,900feet). The lichen contains gyrophoric acid, lecanoric acid, and umbilicaric acid, which are lichen products that can be detected using thin-layer chromatography. The species epithet subglobosum refers to the somewhat spherical pseudisidia.