It is believed that the development of the arbuscular mycorrhizal symbiosis played a crucial role in the initial colonisation of land by plants and in the evolution of the vascular plants.
It has been said that it is quicker to list the plants that do not form mycorrhizae than those that do.This symbiosis is a highly evolved mutualistic relationship found between fungi and plants, the most prevalent plant symbiosis known, and AM is found in 80% of vascular plant families of today.
[ http://en.wikipedia.org/wiki/Arbuscular_mycorrhiza ]
Nutrients can be shown to move between different plants through the fungal network (sometimes called the wood wide web).
[ http://en.wikipedia.org/wiki/Mycorrhiza ]
This picture made my day.
It’s mechanism of how a plant adopts bacteria for better nitrogen acquisition. Note the “hug”!