Mycorrhizae aremutualistic associations between fnugi and vasculas plants (trees,flowers,vegetables,and other complex plants). The term mycorrhizae literally means "fungusroots." Over 500 species of fungi participate in mycorrhizal associations,and the roots of over 80 percent of all vascular planta are believed to have these fungi (most species of trees,for example ,have fungal partners).Mycorrhizal associations benefit both the fungus and the plant: The fungal cells supply the plant with more nutrients (especially phosphorus)than it can absorb through its roots alone ,the plant supplies the fungus with products of photosyntnthesis that provide the raw materials for its metabolism.The fungus also absorbs water and passes it to the plant,a great advantage to the plant when the soil is dry and sandy.