A new species Diorygma tiantaiense Z.F. Jia, sp. nov. was found, which is characterized by a corticolous thallus with norstictic acid, oval or oblong apothecia, immersed to ± raised discs with white pruina, and large muriform ascospores (120–210 × 35–60 µm). Detailed morphological descriptions, photographs, and a comparison and discussion of similar species are provided. A checklist and key to the species of Diorygma known from China is presented.

Based on morphological, chemical and molecular studies, two new species of the lichen genus Letrouitia are newly described from China. Letrouitia arcuata is distinguished by its arcuate ascospores [8–10(–12)-locular, (28–)33–50(–62.5) × (8–)10–14.5 µm] and L. sinuosa by its ascomata with wavy margins and ascospores with lens-shaped locules [6–8-locular, (18–)19.5–32(–34) × (6.5–)8–14 μm]. In addition, L. magenta is reported for the first time as a new record in China, characterized by small and round ascomata. The descriptions, distribution and phylogenetic analysis of the respective species have been actualized and a key to the Letrouitia species known from China is provided.

1. Usnic acid ([2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione], UA) belongs to a small class of dibenzofurans featuring a distinctive 6-5-6 tricyclic scaffold. Since its i...