Seed plant

{{short description|Plants that reproduce with seeds}} {{Use dmy dates|date=May 2025}} {{Automatic taxobox | name = Seed plants | fossil_range = {{fossilrange|Famennian|Present}} | image = Scots Pine (Pinus sylvestris) - Kristiansand, Norway 2021-08-10.jpg | image_upright = 1.0 | image_caption = Scots pine, ''Pinus sylvestris'', a member of the Pinophyta | image2 = Acer pseudoplatanus Chaltenbrunnen.jpg | image2_upright = 1.0 | image2_caption = Sycamore maple, ''Acer pseudoplatanus'', a member of the Eudicots | taxon = Spermatophytes/Plantae | authority = | subdivision_ranks = Extant divisions | subdivision = *Gymnospermae ** Cycadophyta ** Ginkgophyta ** Pinophyta ** Gnetophyta * Angiospermae | synonyms = *Phanerogamae }}

A '''seed plant''' or '''spermatophyte''' ({{etymology|grc|''{{wikt-lang|grc|σπέρμα}}'' ({{grc-transl|σπέρμα}})|seed||''{{wikt-lang|grc|φυτόν}}'' ({{grc-transl|φυτόν}})|plant}}; {{lit|seed plant}}),<ref>{{cite Merriam-Webster|spermatophyte |access-date=2025-03-31}}</ref> also called a '''phanerogam''' (taxon '''Phanerogamae''') or a '''phaenogam''' (taxon '''Phaenogamae'''), is any plant that produces seeds. It is a category of embryophyte (i.e. land plant) that includes most of the familiar land plants, including the flowering plants and the gymnosperms, but not ferns, mosses, or algae.

The term ''phanerogam'' or ''phanerogamae'' is derived from Ancient Greek {{lang|grc|φανερός}} ({{Transliteration|grc|phanerós}}), meaning "visible", in contrast to the term "cryptogam" or "cryptogamae" ({{etymology|grc|''κρυπτός'' (kruptós)|hidden}}, and {{lang|grc|γαμέω}} ({{Transliteration|grc|gaméō}}), 'to marry'). These terms distinguish those plants with hidden sexual organs (cryptogamae) from those with visible ones (phanerogamae).

==Description==

The extant spermatophytes form five divisions, the first four of which are classified as gymnosperms, plants that have unenclosed, "naked seeds":<ref name="Judd-2002">{{cite book |last1=Judd |first1=Walter S. |author-link=Walter Stephen Judd |title=Plant systematics, a phylogenetic approach |last2=Campbell |first2=Christopher S. |last3=Kellogg |first3=Elizabeth A. |author-link3=Elizabeth Anne Kellogg |last4=Stevens |first4=Peter F. |author-link4=Peter F. Stevens |last5=Donoghue |first5=Michael J. |author-link5=Michael Donoghue |date=2002 |publisher=Sinauer Associates |isbn=0-87893-403-0 |edition=2 |location=Sunderland, Massachusetts|page=172}}</ref> * Cycadophyta, the cycads, a subtropical and tropical group of plants * Ginkgophyta, a single living species of tree in the genus ''Ginkgo'' * Pinophyta, the conifers, which are cone-bearing trees and shrubs * Gnetophyta, the gnetophytes, woody plants in the relict genera ''Ephedra'', ''Gnetum'', and ''Welwitschia''.

The fifth extant division is the flowering plants, also known as angiosperms or magnoliophytes, the largest and most diverse group of spermatophytes:

* Angiosperms, the flowering plants, possess seeds enclosed in a fruit, unlike gymnosperms. In addition to the five living taxa listed above, the fossil record contains evidence of many extinct taxa of seed plants, among those: * Pteridospermae, the so-called "seed ferns", were one of the earliest successful groups of land plants, and forests dominated by seed ferns were prevalent in the late Paleozoic. * ''Glossopteris'' was the most prominent tree genus in the ancient southern supercontinent of Gondwana during the Permian period. By the Triassic period, seed ferns had declined in ecological importance, and representatives of modern gymnosperm groups were abundant and dominant through the end of the Cretaceous, when the angiosperms radiated.

==Evolutionary history==

[[File:Runcaria megasporangium and cupule drawing.jpg|thumb |upright=0.5 |left |Drawing of ''Runcaria'' megasporangium and cupule, resembling a seed without a solid seed coat]]

A series of evolutionary changes began with a whole genome duplication event in the ancestor of seed plants about {{ma|319}}.<ref name="Jiao-2011">{{cite journal |first1=Yuannian |last1=Jiao |first2=Norman J. |last2=Wickett |first3=Saravanaraj |last3=Ayyampalayam |first4=André S |last4=Chanderbali |first5=Lena |last5=Landherr |first6=Paula E. |last6=Ralph |first7=Lynn P. |last7=Tomsho |first8=Yi |last8=Hu |first9=Haiying |last9=Liang |first10=Pamela S. |last10=Soltis |first11=Douglas E. |last11=Soltis |first12=Sandra W. |last12=Clifton |first13=Scott E. |last13=Schlarbaum |first14=Stephan C. |last14=Schuster |first15=Hong |last15=Ma |first16=Jim |last16=Leebens-Mack |first17=Claude W. |last17=dePamphilis |display-authors=3 |year=2011 |title=Ancestral polyploidy in seed plants and angiosperms |journal=Nature |doi=10.1038/nature09916}}</ref>

A middle Devonian (385-million-year-old) precursor to seed plants from Belgium has been identified predating the earliest seed plants by about 20 million years. ''Runcaria'', small and radially symmetrical, is an integumented megasporangium surrounded by a cupule. The megasporangium bears an unopened distal extension protruding above the multilobed integument. It is suspected that the extension was involved in anemophilous (wind) pollination. ''Runcaria'' sheds new light on the sequence of character acquisition leading to the seed. ''Runcaria'' has all of the qualities of seed plants except for a solid seed coat and a system to guide the pollen to the seed.<ref>{{cite journal |last1=Gerrienne |first1=P. |last2=Meyer-Berthaud |first2=B. |last3=Fairon-Demaret |first3=M. |last4=Streel |first4=M. |last5=Steemans |first5=P. |title=Runcaria, A Middle Devonian Seed Plant Precursor |journal=Science |year=2011 |volume=306 |issue=5697 |pages=856–858 |doi=10.1126/science.1102491 |pmid=15514154 |url=https://www.science.org/doi/abs/10.1126/science.1102491 |archive-date=24 February 2011 |archive-url=https://web.archive.org/web/20110224214858/http://www.sciencemag.org/content/306/5697/856.abstract |url-status=live |s2cid=34269432 |url-access=subscription}}</ref>

''Runcaria'' was followed shortly after by plants with a more condensed cupule, such as ''Spermasporites'' and ''Moresnetia''. Seed-bearing plants had diversified substantially by the Famennian, the last stage of the Devonian. Examples include ''Elkinsia'', ''Xenotheca'', ''Archaeosperma'', "''Hydrasperma''", ''Aglosperma'', and ''Warsteinia''. Some of these Devonian seeds are now classified within the order Lyginopteridales.<ref>{{cite journal |last1=Anderson |first1=John M. |last2=Anderson |first2=Heidi M. |last3=Cleal |first3=Chris J. |date=2007 |title=Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology |url=http://opus.sanbi.org/bitstream/20.500.12143/5611/1/Strelitzia_20_2007.pdf |journal=Strelitzia |volume=20 |pages=1–280}}</ref>

== Phylogeny ==

Seed-bearing plants are a clade within the vascular plants (tracheophytes).<ref name="Wu-2007"/>

=== Internal phylogeny ===

The spermatophytes were traditionally divided into angiosperms, or flowering plants, and gymnosperms, which includes the gnetophytes, cycads,<ref name="Wu-2007">{{cite journal |journal=Molecular Biology and Evolution |year=2007 |volume=24 |issue=6 |pages=1366–1379 |doi=10.1093/molbev/msm059 |title=Chloroplast Genome (cpDNA) of Cycas taitungensis and 56 cp Protein-Coding Genes of Gnetum parvifolium: Insights into cpDNA Evolution and Phylogeny of Extant Seed Plants |last1=Wu |first1=Chung-Shien |last2=Wang |first2=Ya-Nan |last3=Liu |first3=Shu-Mei |last4=Chaw |first4=Shu-Miaw |pmid=17383970 |doi-access=free}}</ref> ginkgo, and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms,<ref name="Palmer-2004">{{cite journal |title=The plant tree of life: an overview and some points of view |first1=Jeffrey D. |last1=Palmer |author-link1=Jeffrey D. Palmer |first2=Douglas E. |last2=Soltis |first3=Mark W. |last3=Chase |author-link3=Mark Wayne Chase |journal=American Journal of Botany |year=2004 |volume=91 |pages=1437–1445 |doi=10.3732/ajb.91.10.1437 |issue=10 |pmid=21652302 |doi-access=free}}</ref> in particular based on vessel elements. However, molecular studies (and some more recent morphological<ref>{{cite journal |journal=The Journal of the Torrey Botanical Society |pages=169–209 |title=Seed ferns and the origin of angiosperms |first1=James A. |last1=Doyle |volume=133 |issue=1 |date=January 2006 |doi=10.3159/1095-5674(2006)133[169:SFATOO]2.0.CO;2 |s2cid=86302668 |issn=1095-5674 |doi-access=free}}</ref><ref>{{Cite journal |last1=Coiro |first1=Mario |last2=Chomicki |first2=Guillaume |last3=Doyle |first3=James A. |date=n.d. |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 |s2cid=91488394 |issn=0094-8373}}</ref> and fossil<ref>{{cite journal |title=A New Permian Gnetalean Cone as Fossil Evidence for Supporting Current Molecular Phylogeny |author=Zi-Qiang Wang |journal=Annals of Botany |year=2004 |volume=94 |issue=2 |pages=281–288 |doi=10.1093/aob/mch138 |pmid=15229124 |pmc=4242163}}</ref> papers) have generally shown a clade of gymnosperms, with the gnetophytes in or near the conifers. For example, one common proposed set of relationships is known as the ''gne-pine hypothesis'' and looks like:<ref>{{cite journal |last1=Chaw |first1=Shu-Miaw |last2=Parkinson |first2=Christopher L. |last3=Cheng |first3=Yuchang |last4=Vincent |first4=Thomas M. |last5=Palmer |first5=Jeffrey D. |author-link5=Jeffrey D. Palmer |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 |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>{{cite journal |last1=Bowe |first1=L. M. |last2=Michelle |first2=L. |last3=Coat |first3=Gwénaële |last4=Claude |year=2000 |title=Phylogeny of seed plants based on all three genomic compartments: Extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers |journal=Proceedings of the National Academy of Sciences |volume=97 |issue=8 |pages=4092–4097 |doi=10.1073/pnas.97.8.4092 |pmid=10760278 |pmc=18159 |bibcode=2000PNAS...97.4092B |doi-access=free}}</ref><ref>{{cite journal |last1=Soltis |first1=Douglas E. |last2=Soltis |first2=Pamela S. |last3=Zanis |first3=Michael J. |year=2002 |title=Phylogeny of seed plants based on evidence from eight genes |journal=American Journal of Botany |volume=89 |issue=10 |pages=1670–1681 |doi=10.3732/ajb.89.10.1670 |pmid=21665594 |doi-access=free}}</ref>

{{clade| style=font-size:100%;line-height:100% |label1='''Spermatophytes''' |1={{clade |label1=Angiosperms |1=(flowering plants) 50px |label2=Gymnosperms |2={{clade |1=Cycads 50px |2=''Ginkgo'' 50px |3={{clade |1={{clade |1=Pinaceae (the pine family) 65px |2=Gnetophytes 80px }} |2=Cupressophytes 50px }} }} }} }}

However, the relationships between these groups should not be considered settled.<ref name="Palmer-2004"/><ref>{{cite journal |title=Dating Dispersal and Radiation in the Gymnosperm Gnetum (Gnetales)—Clock Calibration When Outgroup Relationships Are Uncertain |last1=Won |first1=Hyosig |last2=Renner |first2=Susanne |journal=Systematic Biology |volume=55 |issue=4 |date=August 2006 |pages=610–622 |doi=10.1080/10635150600812619 |pmid=16969937 |doi-access=free}}</ref>

=== Other classifications ===

Other classifications group all the seed plants in a single division, with classes for the five groups:{{citation needed|date=January 2024}} * Division '''Spermatophyta''' ** '''Cycadopsida''', the cycads ** '''Ginkgoopsida''', the ginkgo ** '''Pinopsida''', the conifers, ("Coniferopsida") ** '''Gnetopsida''', the gnetophytes ** '''Magnoliopsida''', the flowering plants, or '''Angiospermopsida'''

A more modern classification ranks these groups as separate divisions (sometimes under the '''Superdivision Spermatophyta'''):{{citation needed|date=January 2024}} * '''Cycadophyta''', the cycads * '''Ginkgophyta''', the ginkgo * '''Pinophyta''', the conifers * '''Gnetophyta''', the gnetophytes * '''Magnoliophyta''', the flowering plants

[[File:Reconstruction_of_Cycadeoidea_life.jpg|thumb|Reconstruction of the extinct order Bennettitales ]]

Unassigned extinct spermatophyte orders, some of them formerly grouped as "Pteridospermatophyta", the polyphyletic "seed ferns".<ref>{{Cite journal |last1=Elgorriaga |first1=Andrés |last2=Escapa |first2=Ignacio H. |last3=Cúneo |first3=N. Rubén |title=Relictual Lepidopteris (Peltaspermales) from the Early Jurassic Cañadón Asfalto Formation, Patagonia, Argentina |url=https://www.journals.uchicago.edu/doi/10.1086/703461 |journal=International Journal of Plant Sciences |date=July 2019 |volume=180 |issue=6 |pages=578–596 |doi=10.1086/703461 |url-access=subscription}}</ref> * †Cordaitales * †Calamopityales * †Callistophytales * †Caytoniales * †Gigantopteridales * †Glossopteridales * †Lyginopteridales * †Medullosales * †Peltaspermales * †Umkomasiales (corystosperms) * †Czekanowskiales * †Bennettitales * †Erdtmanithecales * †Pentoxylales * †Petriellales Taylor et al. 1994 * †Avatiaceae Anderson & Anderson 2003 * †Axelrodiopsida Anderson & Anderson * †Alexiales Anderson & Anderson 2003 * †Hamshawviales Anderson & Anderson 2003 * †Hexapterospermales Doweld 2001 * †Hlatimbiales Anderson & Anderson 2003 * †Matatiellales Anderson & Anderson 2003 * †Arberiopsida Doweld 2001 * †Iraniales E. Taylor et al. 2008 * †Vojnovskyales E. Taylor et al. 2008 * †Hermanophytales E. Taylor et al. 2008 * †Dirhopalostachyaceae E. Taylor et al. 2008

== References == {{Reflist}}

=== Further reading === * Thomas N. Taylor, Edith L. Taylor, and Michael Krings. 2008. ''Paleobotany: The Biology and Evolution of Fossil Plants'', 2nd edition. Academic Press (an imprint of Elsevier): Burlington, MA; New York, NY; San Diego, CA, USA, London, UK. 1252 pages. {{ISBN|978-0-12-373972-8}}. {{Plant classification}} {{botany}} {{Taxonbar|from=Q25814}}

Category:Superphyla Category:Devonian first appearances Category:Plants