Saccardiaceae Höhn., Sber. Akad. Wiss. Wien, Math.-naturw. Kl., Abt. 1 118: 369 [95 repr.] (1909)
Saprobic on leaves. Sexual morph: Ascomata superficial on host tissue, globose to subglobose, initially pale yellow, becoming brown to dark brown, loose, fleshy and soft, solitary or gregarious, ostiole not seen. Peridium very thin-walled, composed of pale yellow to brown cells. Hamathecium lacking. Asci 8-spored, bitunicate, globose to ovoid or saccate, sessile or with pedicel. Ascospores 2–3-seriate, hyaline, oblong to ellipsoidal, with obtuse to rounded ends, muriform. Asexual morph: Undetermined.
Type genus: Saccardia Cooke, Grevillea 7(no. 42): 49 (1878)
Notes: The families Phaeothecoidiellaceae, Saccardiaceae and Schizothyriaceae are a poorly understood assemblage of genera, which mostly lack sequence data. The types of Saccardiaceae and Schizothyriaceae need to be recollected to establish their phylogenetic relationships with other ascomata groups. We provide notes and illustrations for one genus placed in Saccardiaceae and suggest tentative placements for other taxa which were formerly placed in Saccardiaceae in Wijayawardene et al. (2018), acknowledging that they need to be recollected and sequenced to confirm our suggestions. The family Saccardiaceae was established by Höhnel (1909a). Taxa are mostly saprobic on living or dead plants. The understanding of the family by von Arx & Müller (1975) was as follows. Ascomata are small and discoid, disc convex or pulvinate and hyphae develop superficially on the cuticle of leaves or other plant parts, asci are surrounded by numerous pseudoparaphyses, forming an epithecium, mostly saccate, thick-walled, fissitunicate and ascospores are 2–3-celled or multicelled and hyaline or brown. The family comprises 13 genera and has been placed as family incertae sedis within the Ascomycota (Lumbsch & Huhndorf 2010, Wijayawardene et al. 2018).
The family is based on Saccardia which is illustrated from material of S. quercina Cooke in H.W. Ravenel American Exsicata and can be considered part of the type as the collection details match. The globose to ovoid or saccate asci are enclosed in very thin-walled, small ascomata similar to Translucidithyrium thailandicum in Phaeothecoidiellaceae (Zeng et al. 2018). The muriform ascospores, however, are unlike members of Phaeothecoidiellaceae We maintain the family Saccardiaceae based on Saccardia quercina and include the genera Ascolectus, Cyanodiscus, Henningsiella, Phillipsiella, Pseudodiscus and Schenckiella. We were unable to examine Ascolectus, Cyanodiscus, Phillipsiella, Pseudodiscus, and Schenckiella so these remain in Saccardiaceae pending further study. Phookamsak et al. (2016) provided a description and illustration of Henningsiella and tentatively placed it in Saccardiaceae until molecular phylogeny is available to clarify its natural placement. We maintain the family Saccardiaceae to accommodate Saccardia, plus other genera, which were previously placed in this family that we have not been able to examine. The family is characterized by minute ascomata, surrounded by brown mycelial network forming plectenchymatous tissue, with very thin walls and rounded asci with eight muriform ascospores and a habit on leaves. The asexual morph is unknown (Wijayawardene et al. 2017b).