A genus of 15-20 species, nearly cosmopolitan in distribution. This treatment follows Christenhusz et al. (2019) in recognizing 3 subgenera, the monotypic subgenus Paramochaete Chistenhusz & Husby (of n. South America), basal to the two main subgenera (and the ones in our flora -- see key): subgenus Equisetum and subgenus Hippochaete (Milde) Baker.
Ref: Christenhusz et al. (2019); Des Marais et al. (2003); Guillon (2004); Hauke (1993) In Flora of North America Editorial Committee (1993b); Hauke In Kramer & Green (1990); Lellinger (1985); Mickel (1979); Zhang & Turland in FoC (2013). Show full citations.