the chitin in the outer cell walls of fungi forms a protective yet flexible casing. it acts like a shield around the hyphae, allowing them to penetrate dense soil, wood, and, in some species, rock. like roots, hyphae grow at their lips.
tremendous turgor pressure--up to 10 atmospheres--heips propel the lips through soil and wood. (for comparison, the air pressure in a car tirm is 3 atmospheres ) Each hypha stretches in to its environment like a tubular balloon that's continuously inflating. except inflating with watery cytoplasm, not air.
Hyphae branch repeatedly forming a mycelium, the body of a single fungus. By extending hypha into new territory, the mycelium can cover a very large area. The current record holder is a specimen of honey fungus, which was discovered in Oregen in 2000. The fungus extends beneath an area larger than 1600 football fields.