Index to genera of ferns and lycophytes and their family placement. Families listed below are those accepted by Smith et al. (2006, 2008). Numbers in parentheses correspond to family numbers assigned by Smith et al. (2006), and are indicated for each accepted genus. All accepted genera (but not all synonyms) in Pichi Sermolli (1977), Ching (1978), and Kramer (1990) are accounted for. Newly described or recircumscribed genera since 1990 are also included. Accepted names are in roman, synonyms are in italics; for both accepted names and synonyms, the number of species (sometimes approximate) is given, except for synonyms whose circumscription varies sufficiently (or is unclear) such that this number would be relatively meaningless. An asterisk (*) indicates genera likely or soon to undergo redefinition or inclusion in another accepted genus, based on existing morphological and molecular data. Superscript 1 (1) indicates genera in which species circumscription requires more study before limits are clear. Sources for numbers of species include Copeland (1947), Kramer (1990), and several recent publications, e.g., Ebihara et al. (2006), as well as some unpublished information by Smith. IPNI (The International Plant Names Index: http://www.ipni.org/) has also been consulted for many genera, in order to incorporate recently described species in the totals.

For more complete references documenting the family level classification, see Smith et al. (2006, 2008). A few accepted names given herein are not validly published, as, for example, some in Thelypteridaceae (see Smith, in Kramer, 1990) and are indicated by superscript 2 (2).