Summary
Eusporangiate ferns are vascular spore plants, whose sporangia arise from several epidermal cells and not from a single cell as in leptosporangiate ferns. Typically these ferns have reduced root systems and sporangia that produce large amounts of spores (up to 7000 spores per sporangium in Christensenia).
| Eusporangiate ferns | |
|---|---|
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| Botrychium lunaria | |
| Scientific classification | |
| Kingdom: | |
| Division: | |
| (unranked): | Eusporangiate ferns
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| Classes | |
There are four extant eusporangiate fern families, distributed among three classes. Each family is assigned to its own order.[1][2]
- Class Psilotopsida
- Order Psilotales, family Psilotaceae – Whisk ferns (2 genera, about 17 species)
- Order Ophioglossales, family Ophioglossaceae – Adder's-tongues (5 genera, about 80 species)
- Class Equisetopsida
- Order Equisetales, family Equisetaceae – Horsetails (1 genus, about 15 species)
- Class Marattiopsida
- Order Marattiales, family Marattiaceae – Marattoid ferns (6 genera, about 500 species)
The following diagram shows a likely phylogenic placement of eusporangiate fern classes within the vascular plants.[3][4]
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eusporangiate
ferns |
Cladistics edit
While it is generally accepted that the leptosporangiate ferns are monophyletic, it is considered to be likely that the eusporangiate ferns, as a group, are paraphyletic.[5] In each of the three examples from recently published studies, shown in the following table, it can be seen that, together, the four eusporangiate fern families do not form a single clade.
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References edit
- ^ 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. JSTOR 25065646. Archived from the original (PDF) on February 26, 2008.
- ^ 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. doi:10.11646/phytotaxa.19.1.2.
- ^ Paul G. Wolf; Joshua P. Der; Jacob B. Davidson; Kathleen M. Pryer; Aaron M. Duffy; Amanda L. Grusz (2010). "The evolution of chloroplast genes and genomes in ferns" (PDF). Plant Molecular Biology. 76 (3–5): 251–261. doi:10.1007/s11103-010-9706-4. PMID 20976559. S2CID 7552933.[permanent dead link]
- ^ a b Samuli Lehtonen (2011). "Towards Resolving the Complete Fern Tree of Life" (PDF). PLOS ONE. 6 (10): e24851. Bibcode:2011PLoSO...624851L. doi:10.1371/journal.pone.0024851. PMC 3192703. PMID 22022365. Archived from the original (PDF) on 2012-08-08. Retrieved 2012-03-09.
- ^ 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". American Journal of Botany. 91 (10): 1582–1598. doi:10.3732/ajb.91.10.1582. PMID 21652310.
- ^ Kathleen M. Pryer; Eric Schuettpelz (2009). "Ferns" (PDF). In S. Blair Hedges; Sudhir Kumar (eds.). The Timetree of Life. Oxford Biology.
- ^ 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)". American Journal of Botany. 97 (9): 1444–1456. doi:10.3732/ajb.0900305. PMID 21616899.
- Hogan, C.Michael. 2010. Fern. Encyclopedia of Earth, National Council for Science and the Environment. topic ed. Saikat Basu
- Sporne, K. R. 1962. The morphology of pteridophytes, the structure of ferns and allied plants. pp. 127–135. Hutchison & Co. London.