Subgenus
Hippochaete
Equisetum hyemale affine. Photo: (c) Tony Frates, some rights reserved (CC BY-NC-SA)
Equisetum (/ˌɛkwɪˈsiːtəm/; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.