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Scientific classification e
Kingdom: Plantae
Division: Pteridophyta
Class: Psilotopsida
D. H. Scott
Orders & families

Psilotopsida is a class of ferns or fern-like plants, considered to be one of the three classes of eusporangiate ferns.[1] It should not be confused with the obsolete class Psilophytopsida. As circumscribed by Smith et al., 2006,[2] Psilotopsida contains two families, Psilotaceae and Ophioglossaceae, placed in orders Psilotales and Ophioglossales, respectively.[3] The affinities of these two groups have long been unclear and a close relationship between them has only recently been confirmed through molecular systematic studies. Some studies show that Psilotopsida is the sister-group to all other ferns (including Marattiaceae and Equisetaceae),[1][4] but others indicate that Equisetaceae is more basal.[5]


  1. ^ a b Kathleen M. Pryer; Eric Schuettpelz; Paul G. Wolf; Harald Schneider; Alan R. Smith & Raymond Cranfill (2004). "Phylogeny and evolution of ferns (monilophytes) with a focus on the early leptosporangiate divergences" (PDF). American Journal of Botany. 91 (10): 1582–1598. PMID 21652310. doi:10.3732/ajb.91.10.1582. 
  2. ^ Alan R. Smith; Kathleen M. Pryer; Eric Schuettpelz; Petra Korall; Harald Schneider; Paul G. Wolf (2006). "A classification for extant ferns" (PDF). Taxon. 55 (3): 705–731. doi:10.2307/25065646. 
  3. ^ Maarten J. M. Christenhusz, Xian-Chun Zhang & Harald Schneider (2011). "A linear sequence of extant families and genera of lycophytes and ferns" (PDF). Phytotaxa. 19: 7–54. 
  4. ^ Samuli Lehtonen (2011). "Towards Resolving the Complete Fern Tree of Life" (PDF). PLoS ONE. 6 (10): e24851. PMC 3192703Freely accessible. PMID 22022365. doi:10.1371/journal.pone.0024851. 
  5. ^ Hardeep S. Rai & Sean W. Graham (2010). "Utility of a large, multigene plastid data set in inferring higher-order relationships in ferns and relatives (Monilophytes)" (PDF). American Journal of Botany. 97 (9): 1444–1456. PMID 21616899. doi:10.3732/ajb.0900305.