Mycorrhiza is a composite mutualistic association between a fungus and plant root. The fungus receives organic nutrients mainly carbohydrates and vitamins from the plant and in return absorbs mineral salts and water which pass to plant root. The ectotrphic mycorrhiza forms a sheath around the root and penetrates into the intercellular spaces of cortex as in most forest trees. Endotrophic mycorrhiza also forms an intercellular network and appears to enter the cells. Root nodule formed by Rhizobium in leguminous plant is an example of mycorrhiza.