Citation: Pem D et al. (2019) Mycosphere Notes 275-324: A morphotaxonomic revision and typification of obscure Dothideomycetes genera (incertae sedis). Mycosphere 10(1), 1115–1246
Byssocallis Syd. Annls mycol. 25(1/2): 14 (1927)
Parasitic on mycelium of Meliolaceae on leaves of Phoebes jonduzii. Sexual morph: Ascomata superficial, distributed throughout upper and lower surface of leaf, solitary, subglobose-globose, light yellow to orange-brown, with an opening at the centre, concealed with light brown mycelia. Peridium comprising 3–4 layers of pale yellow cells of closely arranged textura angularis. Hamathecium 1–1.5 μm wide comprising numerous filiform, branched, septate pseudoparaphyses embedded in a gelatinous matrix. Asci 8-spored, bitunicate, cylindrical to clavate, slightly curved, short pedicellate, apically rounded with a small ocular chamber. Ascospores fusiform to clavate, upper part wider than lower part, 3-transversely septate, slightly constricted at the septa, hyaline to grayish, slightly granulated, smooth-walled. Asexual morph: Undetermined.
Type species – Byssocallis phoebes Syd.
Notes – Byssocallis was introduced with two species B. capensis (Doidge) Rossman and Byssocallis phoebes Syd. The genus is characterized by reticulate, branched, and septate hyphae with colorless mycelium covering the host. Perithecia are solitary to gregarious, superficial, ostiolate with smooth walls. Paraphyses are numerous, narrow, branched with mucous membrane. Asci are cylindrical, bitunicate, octosporous. Ascospores are clavate, narrowly fusiform, transverse, hyaline, and multiseptate with the ends often constricted. Species in Byssocallis were found similar to those in Melioliphila except they possess luteous granules in outer cell walls of the ascocarps and hyphae forming the stroma. Byssocallis was previously synonymised with Puttemansia by Petrak (1931) and Pirozynski (1977) based on the presence of apiculate ascospores (Rossman 1987). Byssocallis was accepted as a genus in Tubeufiaceae (Lumbsch & Huhndorf 2010). Upon further study, the genus Byssocallis was transferred to Dothideomycetes, genera incertae sedis (Hyde et al. 2013, Boonmee et al. 2014, Kirk et al. 2013, Wijayawardene et al. 2014). The asexual morph of this genus is unknown. We re-examined the syntype of Byssocallis phoebes and found similar morphological characters with species accommodated in the family Perisporiopsidaceae. Boonmee et al. (2017) revised the family Perisporiopsidaceae which is characterized by “superficial ascomata with surrounding mycelia, and ellipsoidal oblong, 1 or more septate, hyaline ascospores”. Therefore, the genus should be placed in Perisporiopsidaceae (= Parodiopsidaceae) based on morphology.