Ophioglossaceae , the Adder's tongue family, 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 fourgenera, Ophioglossum, Botrychium, Helminthostachys, and Mankyua (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). A notable exception is the classification of Kato (1987), who advocated the division of Botrychium into four genera: Botrychium s.s., Sceptridium, Japanobotrychium, and Botrypus.
These ferns differ from the other ferns in several respects:
Members of Ophioglossaceae are usually terrestrial (excepting a few epiphytic species of Ophioglossum) and occur in both temperate and tropical areas. The leaves are usually fleshy, and in temperate areas will often turn brownish or reddish during colder months. In addition to having mycoheterotrophic gametophytes, there are a few members of Botrychium that are unique among ferns in having the sporophytes also mycoheterotrophic, producing only small, ephemeral sporophylls that do not photosynthesize.
The genera Botrychium (with its segregate genera Botrypus, Japanobotrychium and Sceptridium) and Helminthostachys are sometimes placed in their own families, Botrychiaceae and Helminthostachyaceae, respectively.
PTERIDOPHYTES OF NORTHEAST ALABAMA AND ADJACENT HIGHLANDS III: OPHIOGLOSSALES AND POLYPODIALES (Aspleniaceae to Dennstaedtiaceae).
Jan 01, 2001; INTRODUCTION Members of Ophioglossales and Polypodiales belong to the division Polypodiophyta and are often called "true ferns."...