Seed plant

Seed plants Temporal range: Famennian–Present PreꞒ Ꞓ O S D C P T J K Pg N
Scots pine, Pinophyta
Sycamore maple, Acer pseudoplatanus, a member of the Eudicots
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Spermatophytes
Extant divisions
Gymnospermae Cycadophyta Ginkgophyta Pinophyta Gnetophyta Angiospermae
Synonyms
Phanerogamae Phaenogamae

A seed plant or spermatophyte (lit. 'seed plant'; from

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

• Cycadophyta
  , the cycads, a subtropical and tropical group of plants,
• Ginkgophyta, which includes a single living species of tree in the genus Ginkgo
  ,
• Pinophyta, the conifers, which are cone-bearing
  trees and shrubs, and
• 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.

• 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

Evolutionary history

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

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]

Phylogeny

Seed-bearing plants are a

The spermatophytes were traditionally divided into

Spermatophytes	Angiosperms (flowering plants) Gymnosperms Cycads Ginkgo Pinaceae (the pine family) Gnetophytes other conifers

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 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]}

• Cycadophyta, the cycads
• Ginkgophyta
  , the ginkgo
• Pinophyta
  , the conifers
• Gnetophyta
  , the gnetophytes
• Magnoliophyta, the flowering plants

Unassigned extinct spermatophyte orders, some of which qualify as "seed ferns":^{[citation needed]}

• †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