If you're studying A-level or IB-level Biology at school in the UK, then a new site might give you a helping hand. If you're outside the UK, it's still worth looking into as quite a bit if the information applies...
Archive - September 7, 2015
Alun Salt
Mycorrhizal fungi and distribution of specialized orchids
The use of a widespread fungal operational taxonomic unit in P. deformis enables a broad distribution despite high mycorrhizal specificity.
botanyone