Orchids rely on fungi to reproduce. Their tiny seeds don’t have any on-board nutrients (like beans or apples) and will not germinate until they are infected by a symbiotic fungus which supplies them with food.
Known as a protocorm, this tiny orchid-fungus ball grows, turns green and eventually starts to photosynthesise.
Because each species of orchid depends on a relatively small number of compatible fungi species, some orchids have proven very difficult to cultivate artificially.