Four new species of Cryptothecia (Arthoniaceae, Ascomycota) and Myriostigma (Arthoniaceae, Ascomycota) from China, based on morphology and molecular phylogeny

In this study, morphological and molecular phylogenetic approaches were used to investigate the species diversity of <i>Cryptothecia</i> and <i>Myriostigma</i> from southern China. We found four new species of <i>Cryptothecia</i> and <i>Myriostigma</i> (<i>C.disjecta</i>, <i>C.sorediatum</i>, <i>M.melanovillosa</i> and <i>M.visus-blotch</i>). <i>Cryptotheciadisjecta</i> is distinguished by verrucose pseudisidia that are loosely scattered on the thallus, the upper parts of which are white or have darker dots. <i>Cryptotheciasorediatum</i> is distinguished by I- medulla and thalli having globose soralia. <i>Myriostigmamelanovillosa</i> is distinguished by thalli with black or purple dots and hyaline to pale yellow ascospores (63-71 × 26-33 µm). <i>Myriostigmavisus-blotch</i> is distinguished by hyaline ascospores and ascigerous areas, which have many irregular small patches that are scattered or clustered together radially elongated. In addition, a phylogenetic tree based on mtSSU, RPB2 and nuLSU illustrates the phylogenetic placement of the proposed four new taxa. Detailed descriptions of the morphological, ecological and chemical characteristics and illustrations of each species are provided. Two updated keys for all known Chinese <i>Cryptothecia</i> and <i>Myriostigma</i> species are also provided.