define mycorrhizal fungi
Definition of MYCORRHIZA. : the symbiotic association of the mycelium of a fungus with the roots of a seed plant.â myÂ·corÂ·rhiÂ·zal \-zÉl\ adjective.See mycorrhiza defined for kids. ADVERTISEMENT. the symbiotic association of the mycelium of a fungus with the roots of a seed plant. â myÂ·corÂ·rhiÂ·zal \-zÉl\ adjective. See mycorrhiza defined for kids.