Mycelium is a fundamental part of fungi and plays a crucial role in their life cycle and ecological functions. It refers to the vegetative, branching network of fine filaments called hyphae that collectively form the body of a fungus. Mycelium is typically found underground, within the substrate it's feeding on, or within decaying organic matter. Mycelium can also reproduce ___________________ through fragmentation. Portions of the mycelium can break off and grow independently, developing into new mycelial colonies. This method is common in fungi that grow in favorable conditions and need to quickly expand their population.