Mycorrhiza: It is a symbiotic association between a fungus and the roots of a vascular plant. Mycorrhiza is found in some genus of gymnosperms; like Pinus.
Coralloid Roots: These roots too show symbiotic association but in this case, the association is with nitrogen fixing cyanobacteria. Many nodules are formed in the roots giving them coralloid appearance. Examples are Cycas and plants of leguminoceae.