Ophioglossaceae is a family of ferns, currently thought to be most closely related to Psilotaceae, the two together comprising the class Psilotopsida as the sibling group to the rest of the ferns. The number of genera included in the family varies between different authors' treatments, and most conservatively the family is treated as containing three genera, Ophioglossum, Botrychium, and Helminthostachys (placed in three separate families in some other treatments). A broad definition of the family and its genera have been taken in several recent treatments (e.g., Wagner 1990, Smith et al. 2006, and in the Flora of North America).