The life cycle of a mushroom begins when two spores of opposite mating types germinate in a growth substrate and send out threads called "hyphae." The hyphae form a clamp connection where genetic information is exchanged and then expand into a web of undifferentiated threads called "mycelium." If the conditions are right, the mycelium organizes itself into a mushroom with special reproductive cells called basidia, which catapult spores into the air and give rise to new mushrooms. 