PubMed · 2026-05-13
Researchers on a Japanese island found that orchids living on tree bark and those growing in soil rely on different fungal partners, yet some key fungi are shared between both habitats — suggesting these fungi helped orchids make the evolutionary leap from ground to canopy.
Epiphytic (tree-dwelling) orchids and terrestrial (ground-dwelling) orchids host distinct mycorrhizal fungal communities, and the bark and soil substrates they grow in also differ in fungal composition.
Overall fungal richness was lower in bark than in soil, but the diversity of rhizoctonia fungi — the main group orchids rely on — was similarly high in both habitats.
Some rhizoctonia fungi were found in both epiphytic and terrestrial orchids and were confirmed to form successful partnerships with orchids from both habitats in laboratory culture, suggesting they acted as a bridge enabling canopy colonization.
