Editing Gnetophyta (section)

===Anthophyte hypothesis===
From the early twentieth century, the anthophyte hypothesis was the prevailing explanation for [[seed plant]] evolution, based on shared [[morphology (biology)|morphological]] characters between the gnetophytes and angiosperms. In this hypothesis, the gnetophytes, along with the extinct order Bennettitales, are sister to the angiosperms, forming the "anthophytes".<ref name=Judd/> Some morphological characters that were suggested to unite the anthophytes include vessels in wood, net-veined leaves (in ''[[Gnetum]]'' only), [[lignin]] chemistry, the layering of cells in the apical [[meristem]], [[pollen]] and [[megaspore]] features (including thin megaspore wall), short cambial initials, and lignin syringal groups.<ref name=Judd/><ref name=Donaghue>
{{cite journal
 | author1 = Donoghue, M.J.
 | author2 = Doyle, J.A.
 | year = 2000
 | title = Seed plant phylogeny: demise of the anthophyte hypothesis?
 | journal = Current Biology
 | volume = 10 | issue = 3 | pages = R106–R109
 | doi = 10.1016/S0960-9822(00)00304-3
 | pmid = 10679315 |s2cid=16558206
| doi-access = free
 | bibcode = 2000CBio...10.R106D
 }}
</ref><ref name=Loconte>
{{cite journal
 | author1 = Loconte, H.
 | author2 = Stevenson, D.W.
 | year = 1990
 | title = Cladistics of the Spermatophyta
 | journal = Brittonia
 | volume = 42 | issue = 3 | pages = 197–211
 | doi = 10.2307/2807216 | jstor = 2807216
 | bibcode = 1990Britt..42..197L
 |s2cid=36908568
}}
</ref><ref name=Nixon>
{{cite journal
 | author1 = Nixon, K.C.    | author2 = Crepet, W.L.
 | author3 = Stevenson, D.  | author4 = Friis, E.M.
 | year = 1994
 | title = A reevaluation of seed plant phylogeny
 | journal = Annals of the Missouri Botanical Garden
 | volume = 81 | issue = 3 | pages = 494–533
 | doi = 10.2307/2399901 | jstor=2399901
 | url=https://www.biodiversitylibrary.org/part/30316
}}
</ref> However, most genetic studies, as well as more recent morphological analyses,<ref name=Coiro>
{{cite journal
 | author1 = Coiro, M.
 | author2 = Chomicki, G.
 | author3 = Doyle, J.A.
 | year = 2018
 | title = Experimental signal dissection and method sensitivity analyses reaffirm the potential of fossils and morphology in the resolution of the relationship of angiosperms and Gnetales
 | journal = Paleobiology
 | volume = 44 | issue = 3  | pages =  490–510
 | doi = 10.1017/pab.2018.23 | bibcode = 2018Pbio...44..490C
 |s2cid=91488394
}}
</ref> have rejected the anthophyte hypothesis.<ref name="Bowe" /><ref name="Chaw">
{{cite journal
 | author1 = Chaw, S.M.  | author2 = Aharkikh, A.
 | author3 = Sung, H.M.  | author4 = Lau, T.C.
 | author5 = Li, W.H.
 | year = 1997
 | title = Molecular phylogeny of extant gymnosperms and seed plant evolution: Analysis of nuclear 18S rRNA sequences
 | journal = Molecular Biology and Evolution
 | volume = 14 | issue = 1 | pages = 56–68
 | pmid = 9000754
 | doi=10.1093/oxfordjournals.molbev.a025702 | doi-access = free
}}
</ref><ref name="Qui" /><ref name="Magallon" /><ref name="Sanderson" /><ref name = "Chaw2">
{{cite journal
 | author1 = Chaw, S.M.   | author2 = Parkinson, C.L.
 | author3 = Cheng, Y.    | author4 = Vincent, T.M.
 | author5 = Palmer, J.D.
 | year = 2000
 | title = Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers
 | journal = Proceedings of the National Academy of Sciences USA
 | volume = 97 | issue=8 | pages = 4086–4091
 | doi = 10.1073/pnas.97.8.4086 | pmid=10760277
 | pmc=18157 |bibcode=2000PNAS...97.4086C
| doi-access = free
 }}
</ref><ref name=Goremykin>
{{cite journal
 | author1 = Goremykin, V.   | author2 = Bobrova, V.
 | author3 = Pahnke, J.      | author4 = Troitsky, A.
 | author5 = Antonov, A.     | author6 = Martin, W.
 | year = 1996
 | title = Noncoding sequences from the slowly evolving chloroplast inverted repeat in addition to rbcL data do not support gnetalean affinities of angiosperms
 | journal = Molecular Biology and Evolution
 | volume = 13  | issue = 2  | pages = 383–396
 | pmid = 8587503
 | doi=10.1093/oxfordjournals.molbev.a025597 | doi-access = free
}}
</ref><ref name=Hajibabaei>
{{cite journal
 | author1 = Hajibabaei, M.
 | author2 = Xia, J.
 | author3 = Drouin, G.
 | year = 2006
 | title = Seed plant phylogeny: Gnetophytes are derived conifers and a sister group to Pinaceae
 | journal = Molecular Phylogenetics and Evolution
 | volume = 40  | issue = 1  | pages = 208–217
 | doi = 10.1016/j.ympev.2006.03.006 | pmid = 16621615
}}</ref><ref name=Hansen>
{{cite journal
 | author1 = Hansen, A.       | author2 = Hansmann, S.
 | author3 = Samigullin, T.   | author4 = Antonov, A.
 | author5 = Martin, W.
 | year = 1999
 | title = Gnetum and the angiosperms: molecular evidence that their shared morphological characters are convergent rather than homologous
 | journal = Molecular Biology and Evolution
 | volume = 16  | issue = 7  | pages = 1006–1009
 | doi=10.1093/oxfordjournals.molbev.a026176  | doi-access = free
}}
</ref><ref name=Samigullin>
{{cite journal
 | author1=Samigullin, T.K.   | author2=Martin, W.F.
 | author3=Troitsky, A.V.     | author4=Antonov, A.S.
 | year = 1999
 | title = Molecular data from the chloroplast rpoC1 gene suggest a deep and distinct dichotomy of contemporary spermatophytes into two monophyla: gymnosperms (including Gnetalaes) and angiosperms
 | journal = Journal of Molecular Evolution
 | volume = 49  | issue = 3  | pages = 310–315
 | doi = 10.1007/PL00006553
 |bibcode=1999JMolE..49..310S  |s2cid=4232968  | pmid = 10473771
}}
</ref>{{Excessive citations inline|date=January 2022}}

Several of these studies have suggested that the gnetophytes and angiosperms have independently derived characters, including flower-like reproductive structures and tracheid vessel elements, that appear shared but are actually the result of parallel evolution.<ref name="Bowe" /><ref name="Judd" /><ref name="Chaw2" />

{{clade 
  |1=''Ginkgo'' 
  |2=cycads  
  |3=[[conifer]]s 
  |label4=anthophytes
  |4={{clade 
    |1=angiosperms (flowering plants)  
    |2=gnetophytes
  }}
}}