Like a disappearing act in a magic show, morel mushrooms seem to emerge from the ground overnight and disappear just as quickly. However, from spores, morel mushrooms pass through five or more stages before becoming the fruiting bodies morel hunters harvest and consume.
The morel mushrooms that produce in the spring are actually only the fruit of the fungus. Underground a root system, referred to as a mycelium, grows year-round waiting for the exact conditions necessary to produce fruit.
Spores of the morel mushroom germinate and become mycelium under the surface of the soil. Mycelium develops sclerotium that helps the fungus survive harsh weather conditions in the winter. Under the most suitable growing conditions, sclerotium develops into fruiting bodies. If suitable conditions to not exist, the sclerotium forms into a new, secondary mycelium to wait until the next spring for another chance at developing into a mushroom.
Mycelium and sclerotium can exist in the ground for years without ever producing fruit. Tom Volk at the University of Wisconsin reports on the school's website that the morel mushroom’s underground growth can cycle between mycelia and sclerotial stages for as long as 80 to 100 years before producing fruit.