Biology:Seed plant

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Short description: Clade of seed plants

Seed plants
Temporal range: Famennian–Present
Scots pine, Pinus sylvestris, a member of the Pinophyta
Acer pseudoplatanus Chaltenbrunnen.jpg
Sycamore maple, Acer pseudoplatanus, a member of the Eudicots
Scientific classification e
Kingdom: Plantae
Clade: Tracheophytes
Clade: Spermatophytes
Extant divisions
  • Phanerogamae
  • Phaenogamae

A seed plant or spermatophyte (lit. seed plant; from grc σπέρματος (spérmatos) 'seed', and φυτόν (phytón) 'plant'), also known as 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 the Greek φανερός (phanerós), meaning "visible", in contrast to the term "cryptogam" or "cryptogamae" (from grc κρυπτός (kruptós) 'hidden'), together with the suffix γαμέω (gaméō), meaning "to marry". These terms distinguish those plants with hidden sexual organs (cryptogamae) from those with visible ones (phanerogamae).


The extant spermatophytes form five divisions, the first four of which are classified as gymnosperms, plants that have unenclosed, "naked seeds":[1]:172

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

Drawing of Runcaria megasporangium and cupule, resembling a seed without a solid seed coat

A whole genome duplication event in the ancestor of seed plants occurred about 319 million years ago.[2] This gave rise to a series of evolutionary changes that resulted in the origin of modern seed plants.

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 mutlilobed 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.[3]

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.[4]


Seed-bearing plants are a clade within the vascular plants (tracheophytes).[5]

Internal phylogeny

The spermatophytes were traditionally divided into angiosperms, or flowering plants, and gymnosperms, which includes the gnetophytes, cycads,[5] ginkgo, and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms,[6] in particular based on vessel elements. However, molecular studies (and some more recent morphological[7][8] and fossil[9] 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:[10][11][12]

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However, the relationships between these groups should not be considered settled.[6][13]

Other classifications

Other classifications group all the seed plants in a single division, with classes for the five groups:Lua error: Internal error: The interpreter exited with status 1.

A more modern classification ranks these groups as separate divisions (sometimes under the Superdivision Spermatophyta):Lua error: Internal error: The interpreter exited with status 1.

Unassigned extinct spermatophyte orders, some of which qualify as "seed ferns":Lua error: Internal error: The interpreter exited with status 1.


  1. Judd, Walter S.; Campbell, Christopher S.; Kellogg, Elizabeth A.; Stevens, Peter F.; Donoghue, Michael J. (2002). Plant systematics, a phylogenetic approach (2 ed.). Sunderland, Massachusetts: Sinauer Associates. ISBN 0-87893-403-0. 
  2. Jiao, Yuannian; Wickett, Norman J; Ayyampalayam, Saravanaraj et al. (2011). "Ancestral polyploidy in seed plants and angiosperms". Nature. doi:10.1038/nature09916. 
  3. Gerrienne, P.; Meyer-Berthaud, B.; Fairon-Demaret, M.; Streel, M.; Steemans, P. (2011). "Science Magazine". Runcaria, A Middle Devonian Seed Plant Precursor (American Association for the Advancement of Science) 306 (5697): 856–858. doi:10.1126/science.1102491. PMID 15514154. Retrieved March 22, 2011. 
  4. Anderson, John M.; Anderson, Heidi M.; Cleal, Chris J. (2007). "Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology". Strelitzia 20: 1–280. 
  5. 5.0 5.1 Chung-Shien Wu, Ya-Nan Wang, Shu-Mei Liu and Shu-Miaw Chaw (2007). "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". Molecular Biology and Evolution 24 (6): 1366–1379. doi:10.1093/molbev/msm059. PMID 17383970. 
  6. 6.0 6.1 Palmer, Jeffrey D.; Soltis, Douglas E.; Chase, Mark W. (2004). "The plant tree of life: an overview and some points of view". American Journal of Botany 91 (10): 1437–1445. doi:10.3732/ajb.91.10.1437. PMID 21652302. 
  7. James A. Doyle (January 2006). "Seed ferns and the origin of angiosperms". The Journal of the Torrey Botanical Society 133 (1): 169–209. doi:10.3159/1095-5674(2006)133[169:SFATOO2.0.CO;2]. ISSN 1095-5674. 
  8. Coiro, Mario; Chomicki, Guillaume; Doyle, James A. (n.d.). "Experimental signal dissection and method sensitivity analyses reaffirm the potential of fossils and morphology in the resolution of the relationship of angiosperms and Gnetales". Paleobiology 44 (3): 490–510. doi:10.1017/pab.2018.23. ISSN 0094-8373. 
  9. Zi-Qiang Wang (2004). "A New Permian Gnetalean Cone as Fossil Evidence for Supporting Current Molecular Phylogeny". Annals of Botany 94 (2): 281–288. doi:10.1093/aob/mch138. PMID 15229124. 
  10. Chaw, Shu-Miaw; Parkinson, Christopher L.; Cheng, Yuchang; Vincent, Thomas M.; Palmer, Jeffrey D. (2000). "Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers". Proceedings of the National Academy of Sciences 97 (8): 4086–4091. doi:10.1073/pnas.97.8.4086. PMID 10760277. Bibcode2000PNAS...97.4086C. 
  11. Bowe, L. M.; Michelle, L.; Coat, Gwénaële; Claude (2000). "Phylogeny of seed plants based on all three genomic compartments: Extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers". Proceedings of the National Academy of Sciences 97 (8): 4092–4097. doi:10.1073/pnas.97.8.4092. PMID 10760278. Bibcode2000PNAS...97.4092B. 
  12. Soltis, Douglas E.; Soltis, Pamela S.; Zanis, Michael J. (2002). "Phylogeny of seed plants based on evidence from eight genes". American Journal of Botany 89 (10): 1670–1681. doi:10.3732/ajb.89.10.1670. PMID 21665594. 
  13. Won, Hyosig; Renner, Susanne (August 2006). "Dating Dispersal and Radiation in the Gymnosperm Gnetum (Gnetales)—Clock Calibration When Outgroup Relationships Are Uncertain". Systematic Biology 55 (4): 610–622. doi:10.1080/10635150600812619. PMID 16969937. 

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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.

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