Description: A leafless non-flowering perennial with hollow, jointed stems, growing up to 40cm tall. It looks like a miniature Christmas tree, and has spreading green teeth on the stem sheath.
Habitat: Roadsides, gardens and waste ground.
Distribution: Throughout the British Isles, and widespread in Europe, Asia and North America.
Related species: Two other of the nine species found in the British Isles have a traditional medicinal use: wood horsetail (E. sylvaticum), similar to field horsetail but more delicate and drooping at the tip; and rough horsetail (E. hyemale), which has no branches. The other species are not used for medicine.
Parts used: Above- ground parts harvested in summer.