Phaeoclavulina was previously placed in the genus Ramaria subgenus Echinoramaria. Phaeoclavulina has a broad distribution from temperate to tropical regions worldwide. One of its species, P. aeruginea, is acknowledged to be an interesting coral fungus with blue to blue-green apical branches as the distinctive character. To date, there has been no information on the occurrence of P. aeruginea in Indonesia. In 2023, the Indonesian mushroom hunter community obtained some unusual specimens of coral fungi that resembling P. cyanocephala and P. aeruginea during a mushroom hunting in West Kalimantan. The goal of this study was to ensure the taxonomical position of our coral fungi specimens based on morphological evidence. The fresh specimens were subjected to morphological and molecular investigation. The basidiomata were described based on the macro- and micromorphological features. Molecular analysis using ITS 1/2 sequences was conducted to construct a phylogenetic tree. We confirmed our specimen as Phaeoclavulina aeruginea (P. Zhang) FIPIA-DEP44 was easily distinguished from other species of Phaeoclavulina by the greenish blue apical color on the branches of fruiting bodies, having 2 sterigmata on basidia, and produced spiky spores with nodes (echinulates) on its surface. However, P. aeruginea is difficult to distinguish morphologically from P. cyanocephala.  The BLAST comparison of our specimen revealed a 96% similarity to P. aeruginea from China as the top hits. In addition, the phylogenetic tree (Maximum Likelihood) placed our specimens within the P. aeruginea clade (BS value 100%). The current study reveals the information on distribution of P. aeruginea in Indonesia after previously reported from China.

Index Terms- Coral fungus, taxonomy, new record, west Kalimantan