Spanish moss (Tillandsia usneoides) closely resembles its namesake (Usnea, or beard lichen). However, Spanish moss is not biologically related to either mosses or lichens. Instead, it is a flowering plant in the family Bromeliaceae (the bromeliads) that grows hanging from tree branches in full sun or partial shade. Formerly this plant has been placed in the genera Anoplophytum, Caraguata, and Renealmia. It ranges from the southeastern United States (southern Virginia and eastern Maryland) to Argentina, growing wherever the climate is warm enough and has a relatively high average humidity.
The plant consists of a slender stem bearing alternate thin, curved or curly, heavily scaled leaves 2–6 cm long and 1 mm broad, that grow vegetatively in chain-like fashion (pendant) to form hanging structures 1–2 m in length, occasionally more. The plant has aerial roots and its flowers are tiny and inconspicuous. It propagates both by seed and vegetatively by fragments that blow on the wind and stick to tree limbs, or are carried by birds as nesting material.
Spanish moss is an epiphyte (a plant that lives upon other plants; from Greek "epi"=upon "phyte"=plant), which absorbs nutrients (especially calcium) and water from the air and rainfall. Spanish moss is colloquially known as "air plant". It can grow so thickly on tree limbs that it gives a somewhat "gothic" appearance to the landscape, and while it rarely kills the trees it lowers their growth rate by reducing the amount of light to a tree's own leaves. It also increases wind resistance, which can prove fatal to the host tree in a hurricane.
In the southern U.S., the plant seems to show a preference of growth on southern live oak and bald cypress because of these trees' high rates of foliar mineral leaching (Ca, Mg, K, and P) providing an abundant supply of nutrients to the plant, but it can colonize in other tree species such as sweetgum, crape-myrtle, other oaks, or even pine.
In the southeastern United States, the following tale is told:
Legendary Canadian singer-songwriter Gordon Lightfoot penned a ballad entitled "Spanish Moss".
At one time, some 5,000 tons of Spanish moss were harvested and used in the U.S. alone. The moss is sometimes bought for use in arts and crafts, or for beddings for flower gardens. The plant is commonly believed to be a habitat for chiggers, but only collects the mites after it has touched the ground. Spanish moss in its natural habitat, hanging from trees, does not harbor chiggers.
Spanish moss is also known to have been worn by the women of the Timucua Indian tribe.