Researchers mapped the fungal allies of the Mexican pinyon pine (Pinus cembroides), an endemic species under pressure from climate change and logging. They identified 63 ectomycorrhizal species across 25 genera, with Cenococcum geophilum and Inocybe species among the most common. These underground partnerships are essential for tree survival, boosting nutrient uptake and drought resistance. Documenting this fungal network provides a foundation for conservation and sustainable forestry of threatened pine ecosystems in Mexico.