| 词条 | Schizaeales |
| 释义 |
| name = Schizaeales | image = Climbing_fern.jpg | image_caption = Lygodium japonicum | taxon = Schizaeales | authority = Schimp. | subdivision_ranks = Families | subdivision =
}} Schizaeales is an order of ferns (class Polypodiopsida). DescriptionWhile the three clades of Schizaeales are all well-distinguished from one another by numerous morphological characters, members of the order all have dimorphic fertile and sterile fronds and lack well-defined sori. Their sporangia have a horizontal annulus that lies below and completely encircles the top of the sporangium.[1] ClassificationIn the molecular phylogenetic classification of Smith et al. in 2006, the Schizaeales were placed in the leptosporangiate ferns, class Polypodiopsida. Three families, Anemiaceae, Lygodiaceae, and Schizaeaceae were recognized.[1] The linear sequence of Christenhusz et al. (2011), intended for compatibility with the classification of Chase and Reveal (2009)[2] which placed all land plants in Equisetopsida,[3] reclassified Smith's Polypodiopsida as subclass Polypodiidae and placed the Schizaeales there, with the same three families.[2] The classification of Christenhusz and Chase (2014) placed all members of the Schizaeales in a more broadly defined Schizaeaceae, reducing the three existing families to subfamilies as Anemioideae, Lygodioideae, and Schizaeoideae.[4] The PPG I classification (2016) returned to the three-family definition of the order.[5] Historically, the ferns in this order were once all lumped into the family Schizaeaceae in the old order Filicales. However, although they are demonstrably related, these ferns differ markedly, and so three groups have now been elevated to family status:
At one time some workers believed the water ferns (order Salviniales) to be allied to this order because of certain structural similarities,[6] but modern cladistic studies have ruled out any special alliance. EvolutionSchizaeales had a northern hemisphere concentration as late as the Mesozoic, but by the Quaternary, there was a clear shift to a southern hemisphere distribution.{{citation needed|date=November 2018}} References1. ^1 {{cite journal |last=Smith |first=Alan R. |last2=Pryer |first2=Kathleen M. |last3=Schuettpelz |first3=Eric |last4=Korall |first4=Petra |last5=Schneider |first5=Harald |last6=Wolf |first6=Paul G. |title=A classification for extant ferns |journal=Taxon |volume=55 |issue=3 |date=August 2006 |pages=705–731 |doi=10.2307/25065646 |url=https://www.fieldmuseum.org/sites/default/files/smith-et-al-taxon-2006.original.pdf}} 2. ^1 {{cite journal |first1=Maarten J. M. |last1=Christenhusz |authorlink1=Maarten J. M. Christenhusz |first2=Xian-Chun |last2=Zhang |first3=Harald |last3=Schneider |date=18 February 2011 |title=A linear sequence of extant families and genera of lycophytes and ferns |journal=Phytotaxa |volume=19 |pages=7–54 |url=http://www.mapress.com/phytotaxa/content/2011/f/pt00019p054.pdf |format=PDF}} 3. ^{{cite journal |last1=Chase |first1=Mark W. |authorlink1=Mark Wayne Chase |last2=Reveal |first2=James L. |authorlink2=James L. Reveal |title=A phylogenetic classification of the land plants to accompany APG III |journal=Botanical Journal of the Linnean Society |volume=161 |issue=2 |date=October 2009 |doi=10.1111/j.1095-8339.2009.01002.x}} 4. ^{{cite journal |last1=Christenhusz |first1=Maarten J. M. |last2=Chase |first2=Mark W. |title=Trends and concepts in fern classification |journal=Annals of Botany |volume=113 |issue=4 |date=13 February 2014 |pages=571–594 |doi=10.1093/aob/mct299|pmc=3936591 }} 5. ^{{cite journal |author=The Pteridophyte Phylogeny Group |title=A community-derived classification for extant lycophytes and ferns |journal=Journal of Systematics and Evolution |volume=54 |issue=6 |pages=563–603 |date=November 2016 |doi=10.1111/jse.12229}} 6. ^{{cite journal |last=Pichi Sermolli |first=R. E. G. | authorlink=Rodolfo Emilio Giuseppe Pichi-Sermolli |title=An historical review of the higher classification of the Filicopsida |journal=Botanical Journal of the Linnean Society |volume=67 |issue=Supplement No. 1 |year=1973 |page=21}}
2 : Pteridopsida|Schizaeales |
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