Introduction: A mycorrhiza is a mutualistic relationship between fungal hyphae and the roots of true plants. The fungal hyphae increase the absorptive surface area of the roots of the plant by aiding in the absorption of water, phosphorus, and other mineral ions from the soil to the roots of the plant. The plant is photosynthetic and provides the fungus with carbohydrates. 6. Read the introduction and provide an explanation for why one group of plants grew better than the other group of plants.