Melomastia Nitschke ex Sacc. Notes. Melomastia (Pleurotremataceae Walt. Watson) was established by Saccardo (1875) to accommodate M. mastoidea (Fr.) J. Schröt (= Melomastia friesii Nitschke) as the type species (Kang et al. 1999). Melomastia is characterized by immersed, ostiolar ascomata, brown to dark brown and comprising several layers of peridium, flexuose and filamentous paraphyses, 8 - spored, cylindrical asci, ovoid, hyaline, 1–11 - septate, fusiform to oblong ascospores with rounded or acute ends, with or without gelatinous sheath ascospores (Norphanphoun et al. 2017; Dayarathne et al. 2020; Li et al. 2022; Kularathnage et al. 2023; Xu et al. 2024). Norphanphoun et al. (2017) introduced Melomastia italica Norph., Camporesi, T. C. Wen & K. D. Hyde based on morphological characteristics and multi-locus phylogeny analyses, and the study revealed that M. italica and Dyfrolomyces maolanensis Jin F. Zhang, Jian K. Liu, K. D. Hyde & Zuo Y. Liu form a distinct lineage, leading D. maolanensis to be synonymized under M. maolanensis. Additionally, Dyfrolomyces and Melomastia species exhibit morphological similarities; however, the relationship between these two genera remains unclear due to the limited availability of sequence data for Melomastia compared to the closely related genera and the change in ascomata morphology with different habitats. The generic delimitation within the family Pleurotremataceae has limited taxonomic significance when it is based on morphological characteristics; thus, 11 species of Dyfrolomyces were synonymized under Melomastia by Li et al. (2022) after they noted the lack of discernible morphological differences between the two genera. However, phylogenetic analyses revealed that Melomastia tiomanensis K. L. Pang, Alias, K. D. Hyde, Suetrong & E. B. G. Jones and M. chromolaenae (Mapook and K. D. Hyde) W. L. Li, Maharachch. & Jian K. Liu form a well-supported basal clade within the Melomastia lineage. Based on these findings and morphological characteristics, Kularathnage et al. (2023) reinstated Dyfrolomyces to accommodate M. tiomanensis and M. chromolaenae, and these two species can be distinguished from other Melomastia species by having spindle-shaped, 6–11 - septate ascospores (Pang et al. 2013; Phukhamsakda et al. 2020; Kularathnage et al. 2023). Currently, Melomastia contains 66 epithets in Index Fungorum (http://www.indexfungorum.org/Names/Names.asp, accessed on 30 September 2024). However, the type species M. mastoidea still lacks the available sequence data (Li et al. 2022; Kularathnage et al. 2023).

Published as part of Zhang, Xian, Tibpromma, Saowaluck, Karunarathna, Samantha C., Du, Tian-Ye, Han, Li-Su, Elgorban, Abdallah M., Kumla, Jaturong, Senwanna, Chanokned, Dai, Dong-Qin, Suwannarach, Nakarin & Wang, Hao-Han, 2025, Additions to the saprobic fungi (Ascomycota) associated with macadamia trees from the Greater Mekong Subregion, pp. 1-29 in MycoKeys 113 on pages 1-29, DOI: 10.3897/mycokeys.113.140031