Root fungi, also called mycorrhizal fungi, are symbiotic organsims which associate with the roots of nearly all plants. This is sorghum root infected with the Vesicular-arbuscular mycorrhizal (VAM) fungus Glomus intraradix. The image shows hyphal growth (the thin hairs) and vesicles (little ovals) inside the host's root. Root fungi, also called mycorrhizal fungi, are symbiotic organsims which associate with the roots of nearly all plants.