Polycoccaceae Ertz, Hafellner & Diederich, in Ertz et al., Fungal Diversity 74: 82 (2015).

MycoBank number: MB 814032; Index Fungorum number: IF 814032; Facesoffungi number: FoF 08781, 50 species.

Lichenicolous. Sexual morph: Ascomata arising singly, often becoming grouped, sometimes united by a clypeus or enclosed in galls, immersed with only the ostiole visible to erumpent and the upper half exposed when mature, perithecioid, subglobose to obpyriform, dark brown to black, ostiolate, neck not extended and scarcely distinguishable from the ascomatal wall. Peridium thick or somewhat broader near the ostiole, comprises 3–6 layers of polyhedral pseudoparenchymatous cells, radially compressed in vertical section and roughly isodiametric in surface view, forming a textura angularis, thick, brown to dark brown and continuing below the centrum in outer layers, less intensely pigmented to hyaline with thin-walled cells at inner layers. Hamathecium comprising branched, anastomosing net of thin, septate to remotely septate narrow hyphal filaments, probably trabeculate pseudoparaphyses (paraphysoids), periphyses absent, hymenial gel I+ blue to violet or unchanged. Asci 2–8-spored, bitunicate, fissitunicate, broadly cylindrical to subclavate, shortly stalked, wall thicker in the upper part of mature asci, with a small internal apical beak. Ascospores irregularly distichously arranged in the asci, ellipsoid, brown to dark brown when mature, 1-septate (euseptate), somewhat constricted at the septum, normally equal in size or the upper cell larger and broader, generally rounded or rarely attenuated at apex, smooth or delicately verruculose, sometimes with a gelatinous sheath (adapted from Ertz et al. 2015).

Type: Polycoccum Saut. ex Körb.

Notes: Ertz et al. (2015) included species of Clypeococcum and Polycoccum in phylogenetic analyses and found that members of the two genera formed a new lineage within Trypetheliales. Therefore, the sister family of Trypetheliaceae was introduced and named as Polycoccaceae to accommodate Clypeococcum and Polycoccum based on molecular and morphological data.