Mushroom mycelium is the underground network of thread-like structures called hyphae that fungi use to grow and absorb nutrients. This mycelium plays a crucial role in breaking down organic matter, recycling nutrients in the ecosystem, and forming symbiotic relationships with plants through mycorrhizae. Mycelium can spread over large areas and is essential for the life cycle of mushrooms, which are the reproductive structures of fungi. When conditions are right, mycelium produces mushrooms that release spores, allowing the fungi to reproduce and continue their life cycle.