Fungi of the phylum basidiomycota form mycorrhizal associations with orchids, a type of flowering plant. how do these associations benefit both the fungi and the orchids

The symbiotic associations between the roots of the plants of the family Orchidaceae and a fungus of the phylum Basidiomycota are known as orchid mycorrhizae. All the orchids are myco-heterotrophic at a certain stage in their cycle of life.  

The orchid mycorrhizae are critically essential at the time of the germination of orchid, as the seed of an orchid has virtually no energy reserve and attains its carbon from the fungal symbiont. Several of the adult orchids sustain their fungal symbionts, however, the benefits to the fungus and the adult photosynthetic orchid largely remain unidentified.