In Huafo Mountain, Mouding, Yunnan Province, China, we found black protrusions on the leaf surface of Quercus plants. The collection which we identified as Acrocalymma chuxiongense sp. nov., a new species of Acrocalymmaceae (Pleosporales) is characterised by dome-shaped ascomata, bitunicate asci with pedicel furcate and an ocular chamber and hyaline, obovoid to ellipsoid, 1-septate ascospores.

Morphologically, this species is typical with obovoid to ellipsoid, larger ascospores than other known species in Acrocalymma. Phylogenetic analysis also showed that it represents a distinct clade, distant to any other species of Acrocalymma. Therefore, we introduce it as Acrocalymma chuxiongense, a new species of Acrocalymmaceae. This study is adding to the current situation where there are very few species and lack of teleomorph characteristics.