Horsetail has spreading, perennial, branching stems. Arial stems can be annual or perennial, cylindrical, fluted, with curved branches at simple or jointed nodes. The internodes are usually hollow. The surfaces of the stems are covered with silica. Cones are terminal.
Horsetail is a perennial herb with creeping rhizomes, often forming large colonies; it can reach 70-100 cm in height. The roots are hollow, toothed, jointed. At the tip of the plant is a cone containing spores. The plant contains silicic acid, tartaric acid, protocatechuic methyl esters, caffeic acids isoquercitrin, apigenin and kaempferol as phenolic compounds.
Other compounds: Quercetin 3-O-glucoside, apigenin 5-O-glucoside and dicaffeoyl-meso-tartaric acid. Di-E-caffeoyl-meso-tartaric acid