Aerial Root

An aerial root is any root that develops above ground and is exposed to the air rather than buried in soil. Climbers and epiphytes depend on them most: orchids and air plants use aerial roots to attach themselves high in the rainforest canopy, and ivy climbs by pressing short clinging roots against a wall or trunk. Others do structural work — a banyan drops roots from its branches that reach the ground and thicken into extra trunks, mangroves form a tangle of prop roots, and maize braces itself with a ring of roots at the base of the stem. Some are green and contribute to photosynthesis. On a houseplant they are normal and healthy rather than a fault, and cutting them away removes support the plant is relying on.