Published online by Cambridge University Press: 11 November 2020
A molecular phylogeny of the genus Byssoloma is inferred from mtSSU sequences using Bayesian and maximum likelihood phylogenetic analyses. Byssoloma subdiscordans is resolved as sister to B. citricola rather than to the B. leucoblepharum clade, the B. subundulatum group (species with a compact apothecial margin) is shown to be a monophyletic group, and three species belonging to this group are described as new to science from Hainan Province in China: B. brunneodiscum W. C. Wang & J. C. Wei, with dark brown apothecia, crystals in the excipulum and the presence of 2,5,7-trichloro-3-O-methylnorlichexanthone; B. rubrofuscum W. C. Wang & J. C. Wei, with red-brown apothecia, 3–6-septate ascospores and the presence of 5,7-dichloro-3-O-methylnorlichexanthone; B. melanodiscocarpum W. C. Wang & J. C. Wei, with pure black apothecia, a K+ olive-black hypothecium and the presence of thiophanic acid.