Stigmidium Trevis., Conspect. Verruc.: 17 (1860).
Vegetative hyphae absent. Sexual morph: Ascomata perithecioid, black, globose to subglobose, ostiolate, usually half-immersed to sessile. Ascomatal wall dark brownish black in upper part, paler brown in middle or lower part. Periphysoids originating from the upper wall of the ascomatal cavity, hyaline, branched or not. Interascal filaments lacking. Asci originating from the lower wall of the ascomatal cavity, fissitunicate, saccate, 8-spored, with ascospores irregularly arranged. Ascospores uniseptate, hyaline, but occasionally turning brown when overmature. Asexual morph: Unknown (adapted from Roux and Triebel 1994 and Videira et al. 2017).
Type species: Stigmidium schaereri (A. Massal.) Trevis.
Notes: Stigmidium is characterised by perithecioid, black, globose to subglobose ascomata, saccate, 8-spored asci anduniseptate, hyaline ascospores. Stigmidium differs from other genera in Mycosphaerellaceae in having ascomata with punctiform ostioles, hamathecium of periphyses, with periphysoids, and hyaline uniseptate ascospores. The placement of Stigmidium in Mycosphaerellaceae is doubtful. Fresh collections with DNA sequence data are needed to confirm the taxonomic placement of the genus.