What is mycelium?

The branched, tubular filaments that make up the undifferentiated body, or thallus, of fungi are called mycelia, the plural form of mycelium. Mycelium can range in size from microscopic to visible, developed structures, which can include sclerotia, puffballs and mushrooms.

Soil and other types of substrate often contain large colonies of mycelium. This vegetative state of fungi reproduces asexually, releasing spores at certain periods of its life cycle to form additional fruiting bodies. Mycelium give fungi the ability to take in nutrients from the environment using facilitated transfusion and active transport. Mycelium is extremely important to both terrestrial and aquatic environments due to its role in plant decomposition.