Index Filicum is a continuing series of botanical indices geared to the ferns, or monilophyte clade. As of supplement 5, the index also covered the lycophytes (Lycopodiopsida), and also the horsetails (Equisetum). There are two original works by this name, by Moore and by Christensen; this article is about the series begun by Christensen.

The forward to supplement seven stated that the supplements would be issued every five years from then on. However, since then, no further volume has been issued. Kew Gardens, the publisher of the two most recent supplements, has decided instead to rely on the International Plant Names Index (http://www.ipni.org/index.html -- online).

Index Filicum volumes

• Index Filicum, sive Enumeratio Omnium Generum Specierumque Filicum et Hydropteridum, ab Anno 1753 ad Finem Anni 1905, Descriptorum adjectis Synonymis Principalibus, Area Geographica, etc. by Christensen, Carl Frederik Albert. Hafniae apud H. Hagerup. 1906. lx/744/(2) pp., hardcover.
• Supplement I: Index Filicum, Supplementum (I) 1906-1912. by Christensen, Carl Frederik Albert. Hafniae apud H. Hagerup. 1913. vi/132 pp, hardcover.
• Supplement II: Index Filicum, Supplementum Preliminaire (II), pour les Annees 1913, 1914, 1915, 1916. by Christensen, Carl Frederik Albert. S. A. I Le Prince Bonaparte, Hafniae. 1917. iv/60 pp, hardcover.
• Supplement III: Index Filicum, Supplementum Tertium, pro Annis 1917-1933. by Christensen, Carl Frederik Albert. apud H. Hagerup. 1934. 220 pp, hardcover.
• Supplement IV: Index Filicum, Supplementum Quartum, pro Annis 1934-1960. by Pichi-Sermolli, Rudolfo E. G. International Bureau for Plant Taxonomy and Nomenclature, Utrecht, Netherlands. 1965. vi/370 pp, softcover.
• Supplement V: Index Filicum, Supplementum Quintum pro Annis 1961-1975. by Jarrett, F. M., with collab. of T. A. Bence et al. Clarendon Press, Oxford. 1985. 400 pp, hardcover. ISBN 0-19-85479-7; B 84-29402.
• Supplement VI: Index Filicum: Supplementum Sextum [Supplement 6] pro annis 1976-1990. by Johns, R. J. Royal Botanic Gardens, Kew, UK. 1996. 414pp, softcover. ISBN 1900347113.
• Supplement VII: Index Filicum: Supplementum Septimum [Supplement 7] Pro Annis 1991-1995. by Johns, R. J., P. J. Edwards, R. Davies and K. Challis. Royal Botanic Gardens, Kew, UK. 1997. 124pp, softcover. ISBN 1900347261.

Other Relevant Indices

• Grimes, J. W., and B. S. Parris. Index of Thelypteridaceae. Kew Publishing, Kew Royal Botanical Garden, United Kingdom. 1986. 54pp, PB. ISBN 0-947643-03-6.
• Herter, W. G. Index Lycopodiorum. W. G. Herter, Basel. 1949.
• Ollgaard, Benjamin. Index of the Lycopodiaceae. Kongel. Danske Vidensk. Selsk., Biol. Skr. 34. Copenhagen. 1989. ISBN 87-7304-195-5.
• Reed, Clyde F. Index to Equisetophyta. Reed Herbarium, Baltimore, MD. 1971.
• Reed, Clyde F. Index Selaginellarum. Memorias da Sociedade Broteriana. 1966.
• Reed, Clyde F. Index Isoetales. Boletim da Sociedade Broteriana. 1953.
• Reed, Clyde F. Index Psilotales. Boletim da Sociedade Broteriana, Vol. XL. 30/2 pp., PB. 1966.