Photonectria splendura, from Latin photon (light) and nectria (fungi genus), with splendura (brilliance), is a bioluminescent fungus endemic to tropical caves. It features an arboreal-form fruiting body up to 15 cm tall, with translucent, gelatinous stacked caps and finely veined gills emitting warm golden light contrasting with bluish stipes and substrate. Bioluminescence (420–490 nm) arises from specialized luciferin-luciferase reactions in gills and cap margins. Thriving on decaying wood in cool (5–15 °C), humid microhabitats, it acts as a key decomposer. Taxonomically in Nectriaceae, genus Photonectria, order Hypocreales, it disperses airborne basidiospores from gills. Its extensive mycelium supports nutrient cycling, highlighting its specialized ecological niche and adaptation to subterranean environments.