Horse tail, horsetail or horse's tail may refer to: the tail of a horse Equisetidae, a subclass of living and extinct plants known as horsetails Equisetales, the single extant order of Equisetidae Equisetaceae, the horsetail family, the only extant family of Equisetales Equisetum, horsetail, the only living genus in Equisetaceae Cauda equina ('horse's tail'), a bundle of spinal nerves and spinal nerve rootlets in humans a type of waterfall See also Horsetail Falls (disambiguation) Hippuris, or mare's tail, a flowering plant Ponytail, a human hairstyle Tug (banner), a pole with circularly-arranged horse tail hairs, historically flown by Turkic tribes