Horsetail (Equisetum arvense) is a perennial spore herbaceous plant with a long creeping rhizome with rounded nodules and thin roots. In early spring, the plant forms unbranched reddish-brown stems up to 25 cm high, which end with spore-bearing "spikelets". It has barren branched green jointed stems up to 30-60 cm high, with numerous branches located whorls directed obliquely upward. The stems of vegetative green shoots are hard, rough to the touch.