Brefeldiellaceae E. Müll. & Arx, in Müller & von Arx, Beitr. Kryptfl. Schweiz 11(no. 2): 148 (1962), MycoBank: MB

Foliar epiphytes or parasites on leaves of various hosts worldwide. Sexual state: Thallus relatively large, circular or irregular, or spreading as root-like structures across the leaf surface, brown to black, extremely thin, covering thyriothecia, and covering host tissue with a skin-like layer; cells of thallus consisting of a single layer of somewhat radially arranged cylindrical to cuboid cells, each cell distinct. Thyriothecia circular in outline, flattened, thin-walled, developing under thallus, with numerous asci. Ostioles central. Hamathecium comprising asci, pseudoparaphyses not observed. Asci 8-spored, bitunicate, fissitunicate, saccate, short-pedicellate or sessile, ocular chamber not obvious. Ascospores 2–3-seriate, oblong-ellipsoidal or clavate, hyaline, 1-septate, trans-septate or muriform, smooth-walled. Asexual state: see in notes.

Notes : According to Cooke and Hawksworth (1970) the name Brefeldiellaceae is illegitimate. Eriksson (1981) however, mentioned that Müller and von Arx (1962) referred to a legitimate description by Theissen (of subfam. Brefeldiineae) and suggested the name is therefore legitimate. Eriksson (1981) also mentioned the status of the family is uncertain. In this study we accept Brefeldiellaceae and add several genera. The characters of Brefeldiellaceae are rather confusing and fresh material and molecular data is needed to establish the taxonomic placement of this family and the various genera that we accommodate in this family. The spreading thallus which covers ascomata with a parallel arrangement of cells is typical of the arrangement of cells in the thyriothecia found in Asterinaceae and Microthyriaceae. The asci are however, different to those in Asterinaceae, saccate to cylindro-clavate in Brefeldiellaceae and globose in Asterinaceae. The Brefeldiellaceae may therefore be a sister family to Microthyriaceae. In this monograph we include Acrogenotheca , Saccardinula , Trichopeltina and Trichopeltum in the family mainly because of thallus characteristics and saccate to cylindro-clavate asci. Acrogenotheca (type A. pulcherrima Bat. & Cif.) was described from undetermined leaves collected in Cuba. Unfortunately more than one taxon is represented on the type material. Saccardinula (type S. guaranitica Speg.) is a less convincing member of the family as it has globose asci and muriform spores, while the thallus is less developed. Trichopeltella (type T. montana (Racib.) Höhn.) was described on leaves from Java, Indonesia and although we were only able to find
asexual structures, the thallus is typical of Brefeldiella. The conidia are produced on small conidiogenous cells that line the conidiomata wall and conidia are cylindrical, hyaline and unicellular. Trichopeltella may be a synonym of Brefeldiella. Trichopeltum (type T. hawaiiense Bat. & C.A.A. Costa) was described on leaves of Smilax from Hawaii. This species has a spreading root-like thallus which superficially look similar to those in Teratosphaeriaceae but are made up of cells typical of Brefeldiellaceae.

The arrangement of Brefeldiellaceae as treated here is certainly polyphyletic. Reynolds and Gilbert (2005) also treated this family with similar wide ranging ascal and thallus characters and the genera certainly need recollecting and sequencing to establish a better phylogeny.
Type : Brefeldiella Speg., Boln Acad. nac. Cienc. Córdoba 11(4): 558 (1889), MycoBank: MB 648