Growth Stages of a Mushroom

Mushrooms are fascinating. Some are incredibly beautiful; some are toxic; some are edible; some are noxious parasites, but they are all fascinating forms of life. Whether you want to eradicate them from your yard or grow them for your salad, learning about the life cycle and different stages of mushroom growth can help you accomplish your goal.

Spores are essentially the seeds produced by the fruiting body, the visible, aboveground part of the mushroom. When spores are released they are dispersed by wind, water or animals. Under the right conditions spores germinate under the soil and send out threads called hyphae. Hyphae must find other, compatible hyphae in order to reproduce and continue developing.

When hyphae have fused together they form a network of filaments called the mycelium. This structure is essentially the plant part of a mushroom. It will eventually send up a fruiting body that becomes the mushroom seen above ground. These mycelia can grow indefinitely and become quite large. According to the Australian National Botanic Gardens, a single mycelium of a species of mushroom called Armillaria ostoyae is 2,400 years old and around 2,199 acres in size.

Eventually, a mycelium will form what is known as a hyphal knot. This is the beginning stage of the mushroom you see above ground. As it matures, the hyphal knot becomes what is known as a pinhead, a button-like protrusion above ground. As it begins to take on a more mushroom-like appearance, it is called a primordium.

Primordia are characterized by a protective cover called a veil that keeps the mushroom's gills safe as it grows. Gills are the spore-producing organs located under the mushroom's cap. As the stem grows, the veil breaks free from the cap and remains near the base of the stem. The veil may not always be visible in a mature mushroom. Not all mushrooms have gills under their caps -- some have pores -- but these organs will eventually release spores and begin the cycle over again.