Saprotrophic fungi and fully mycoheterotrophic orchids

Only a few fully mycoheterotrophic (MH) orchids are currently known to be mycorrhizal with saprotrophic, mostly wood-decomposing fungi, instead of ectomycorrhizal fungi. Lee et al. identify mycorrhizal fungi for seven MH orchid species growing in four humid and warm subtropical forests in Taiwan and find that six of them are mycorrhizal with saprotrophic fungi that are either wood- or litter-decaying. They conclude that MH orchids utilizing saprotrophic, non-Rhizoctonia fungi as a carbon and nutrient source are clearly more frequent than hitherto assumed, allowing them to thrive in deeply shaded, light-limiting forest understoreys even without support from ectomycorrhizal fungi.