The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extan ...

, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνόσπερμος ( el, γυμνός, translit=gymnos, lit=naked, label=none and el, σπέρμα, translit=sperma, lit=seed, label=none), literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants ( angiosperms), which are enclosed within an

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

. Gymnosperm seeds develop either on the surface of scales or

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

, which are often modified to form cones, or solitary as in

yew Yew is a common name given to various species of trees. It is most prominently given to any of various coniferous trees and shrubs in the genus ''Taxus'': * European yew or common yew (''Taxus baccata'') * Pacific yew or western yew (''Taxus br ...

, '' Torreya'', '' Ginkgo''. Gymnosperm lifecycles involve

alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of Biological life cycle, life cycle in plants and algae. It consists of a Multicellular organism, multicellular haploid sexual phase, the gametophy ...

. They have a dominant

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

sporophyte A sporophyte () is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase. Life cycle The sporophyte develops from the zygote pr ...

phase and a reduced

haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

gametophyte phase which is dependent on the sporophytic phase. The term "gymnosperm" is often used in

paleobotany Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeogr ...

to refer to all non-angiosperm seed plants. In that case, to specify the modern

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

group of gymnosperms, the term Acrogymnospermae is sometimes used. The gymnosperms and angiosperms together comprise the spermatophytes or seed plants. The gymnosperms are subdivided into five Divisions, four of which, the

Cycadophyta Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...

, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) are still in existence while the Pteridospermatophyta are now extinct. Newer classification place the gnetophytes among the conifers. By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes ('' Gnetum'', '' Ephedra'' and '' Welwitschia''), and '' Ginkgo biloba'' (a single living species). About 65% of gymnosperms are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, but conifers are almost all

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

. Some genera have

mycorrhiza A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant ...

, fungal associations with roots (''Pinus''), while in some others (''Cycas'') small specialised roots called coralloid roots are associated with nitrogen-fixing

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

Diversity and origin

Over 1000 living species of gymnosperm exist. It was previously widely accepted that the gymnosperms originated in the Late Carboniferous period, replacing the lycopsid rainforests of the tropical region, but more recent phylogenetic evidence indicates that they diverged from the ancestors of angiosperms during the Early Carboniferous. The radiation of gymnosperms during the late Carboniferous appears to have resulted from a whole

genome duplication Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

event around . Early characteristics of seed plants are evident in fossil

progymnosperms The progymnosperms are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the gymnosperms, ancestral to acrogymnosperms and angiosperms (flowering plants). They h ...

of the late

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

period around 383 million years ago. It has been suggested that during the mid-Mesozoic era, pollination of some extinct groups of gymnosperms was by extinct species of

scorpionflies Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Endopterygota with about six hundred species in nine Family (biology), families worldwide. Mecopterans ...

that had specialized proboscis for feeding on pollination drops. The scorpionflies likely engaged in pollination mutualisms with gymnosperms, long before the similar and independent coevolution of nectar-feeding insects on angiosperms. Evidence has also been found that mid-Mesozoic gymnosperms were pollinated by Kalligrammatid lacewings, a now-extinct family with members which (in an example of convergent evolution) resembled the modern butterflies that arose far later. Zamia integrifolia02

All gymnosperms are perennial woody plants, apart from the cycads. The soft and highly

parenchymatous Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word � ...

wood in cycads is poorly lignified, and their main structural support comes from an armor of sclerenchymatous leaf bases covering the stem, with the exception of species with underground stems. There are no

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

gymnosperms and compared to angiosperms they occupy fewer ecological niches, but have evolved both parasites (

parasitaxus ''Parasitaxus usta'' is a rare species of conifer of the family Podocarpaceae, and the sole species of the genus ''Parasitaxus''. It is a woody shrub up to 1.8 m found only in the remote, densely forested areas of New Caledonia, first discover ...

epiphyte An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

s ( Zamia pseudoparasitica) and rheophytes ( Retrophyllum minus).

Conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

s are by far the most abundant extant group of gymnosperms with six to eight families, with a total of 65–70 genera and 600–630 species (696 accepted names).Catalogue of Life: 2007 Annual checklist – Conifer database
Most conifers are

evergreens In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

. The

of many conifers are long, thin and needle-like, other species, including most

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdio ...

and some Podocarpaceae, have flat, triangular scale-like leaves. ''

Agathis ''Agathis'', commonly known as kauri or dammara, is a genus of 22 species of evergreen tree. The genus is part of the ancient conifer family Araucariaceae, a group once widespread during the Jurassic and Cretaceous periods, but now largely re ...

'' in Araucariaceae and '' Nageia'' in Podocarpaceae have broad, flat strap-shaped leaves. Cycads are the next most abundant group of gymnosperms, with two or three families, 11 genera, and approximately 338 species. A majority of cycads are native to tropical climates and are most abundantly found in regions near the equator. The other extant groups are the 95–100 species of Gnetales and one species of Ginkgo. Today gymnosperms are the most threatened of all plant groups.

Classification

A formal classification of the living gymnosperms is the "Acrogymnospermae", which form a monophyletic group within the spermatophytes. The wider "Gymnospermae" group includes extinct gymnosperms and is thought to be

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

. The fossil record of gymnosperms includes many distinctive taxa that do not belong to the four modern groups, including seed-bearing trees that have a somewhat fern-like vegetative morphology (the so-called "seed ferns" or

pteridosperm The term Pteridospermatophyta (or "seed ferns" or "Pteridospermatopsida") is a polyphyletic group of extinct seed-bearing plants (spermatophytes). The earliest fossil evidence for plants of this type is the genus ''Elkinsia'' of the late Devonian ...

s). When fossil gymnosperms such as these and the Bennettitales, glossopterids, and ''

Caytonia ''Caytonia'' is an extinct genus of seed ferns. Description ''Caytonia'' has berry like cupules with numerous small seeds arrayed along axes Whole plant reconstructions Different organs attributed to the same original plant can ...

'' are considered, it is clear that angiosperms are nested within a larger gymnospermae clade, although which group of gymnosperms is their closest relative remains unclear. The extant gymnosperms include 12 main families and 83 genera which contain more than 1000 known species. Subclass

Cycadidae Cycadidae is a subclass of Equisetopsida in the sense used by Mark W. Chase and James L. Reveal in their 2009 article "A phylogenetic classification of the land plants to accompany APG III." This subclass comprises the cycads, which include the ...

*Order Cycadales **Family Cycadaceae: '' Cycas'' **Family Zamiaceae: '' Dioon'', ''

Bowenia The genus ''Bowenia'' includes two living and two fossil species of cycads in the family Stangeriaceae, sometimes placed in their own family Boweniaceae. They are entirely restricted to Australia. The two living species occur in Queensland. '' ...

'', ''

Macrozamia ''Macrozamia'' is a genus of around forty species of cycads, family Zamiaceae, all of which are endemic to Australia. Many parts of the plant have been utilised for food and material, most of which is toxic if not processed correctly. Descripti ...

'', '' Lepidozamia'', '' Encephalartos'', ''

Stangeria ''Stangeria eriopus'' is a cycad endemic to southern Africa. It is the sole species in the genus ''Stangeria'', most closely related to the Australian genus ''Bowenia'', with which it forms the family Stangeriaceae. Description ''Stangeria eriop ...

'', ''

Ceratozamia ''Ceratozamia'' is a genus of New World cycads in the family Zamiaceae. The genus contains 27 known currently living species and one or two fossil species. Most species are endemic to mountainous areas of Mexico, while few species extend into the ...

'', '' Microcycas'', ''

Zamia ''Zamia'' is a genus of cycad of the family Zamiaceae, native to North America from the United States (in Georgia and Florida) throughout the West Indies, Central America, and South America as far south as Bolivia. The genus is considered to be ...

'' Subclass

Ginkgoidae Ginkgoidae is a subclass of Equisetopsida in the sense used by Mark W. Chase and James L. Reveal in their 2009 article "A phylogenetic classification of the land plants to accompany APG III." This subclass contains the single extant genus ''Ginkg ...

*Order

Ginkgoales Ginkgoales are a gymnosperm order containing only one extant species: ''Ginkgo biloba'', the ginkgo tree. It is monotypic, (the only taxon) within the class Ginkgoopsida, which itself is monotypic within the division Ginkgophyta . The order incl ...

**Family Ginkgoaceae: '' Ginkgo'' Subclass Gnetidae *Order

Welwitschiales Welwitschiaceae is a family of plants of the order Gnetales with one living species, ''Welwitschia mirabilis'', found in southwestern Africa. Three fossil genera have been recovered from the Crato Formation – late Aptian (Lower Cretaceous) str ...

**Family

Welwitschiaceae Welwitschiaceae is a family of plants of the order Gnetales with one living species, ''Welwitschia mirabilis'', found in southwestern Africa. Three fossil genera have been recovered from the Crato Formation – late Aptian (Lower Cretaceous) str ...

: '' Welwitschia'' *Order Gnetales **Family Gnetaceae: '' Gnetum'' *Order

Ephedrales Ephedraceae is a family of gymnosperms belonging to Gnetophyta, it contains only a single extant genus, ''Ephedra'', as well as a number of extinct genera from the Early Cretaceous. Taxonomy File:Eamesia chinensis.png, '' Eamesia'' File:Chengia ...

**Family Ephedraceae: '' Ephedra'' Subclass

Pinidae Pinidae is a subclass of Equisetopsida in the sense used by Mark W. Chase and James L. Reveal in their 2009 article "A phylogenetic classification of the land plants to accompany APG III." This subclass comprises the conifers. The Pinidae subcla ...

*Order Pinales **Family Pinaceae: '' Cedrus'', '' Pinus'', ''

Cathaya ''Cathaya'' is a genus in the pine family, Pinaceae, with one known living species, ''Cathaya argyrophylla''. ''Cathaya'' is a member of the subfamily Laricoideae, most closely related to ''Pseudotsuga'' and ''Larix''. A second species, ''C. nan ...

'', ''

Picea A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

'', ''

Pseudotsuga ''Pseudotsuga'' is a genus of evergreen coniferous trees in the family Pinaceae (subfamily Laricoideae). Common names for species in the genus include Douglas fir, Douglas-fir, Douglas tree, Oregon pine and Bigcone spruce. '' Pseudotsuga menz ...

'', ''

Larix Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains furth ...

'', '' Pseudolarix'', '' Tsuga'', ''

Nothotsuga ''Nothotsuga'' is a genus of coniferous trees in the family Pinaceae endemic to China. ''Nothotsuga'' contains only one species, ''Nothotsuga longibracteata'', commonly known as the bristlecone hemlock, which is found in southeastern China, in ...

'', '' Keteleeria'', '' Abies'' *Order

Araucariales Araucariaceae – also known as araucarians – is an extremely ancient family of coniferous trees. The family achieved its maximum diversity during the Jurassic and Cretaceous periods and the early Cenozoic, when it was distributed almost world ...

**Family Araucariaceae: ''

Araucaria ''Araucaria'' (; original pronunciation: .ɾawˈka. ɾja is a genus of evergreen Conifer, coniferous trees in the family Araucariaceae. There are 20 extant taxon, extant species in New Caledonia (where 14 species are endemism, ende ...

'', '' Wollemia'', ''

'' **Family Podocarpaceae: '' Phyllocladus'', ''

Lepidothamnus ''Lepidothamnus'' is a genus of conifers belonging to the podocarp family Podocarpaceae. The genus includes three species of dioecious or monoecious evergreen trees and shrubs, and creepers. '' L. intermedius'' and '' L. laxifolius'' are nativ ...

'', ''

Prumnopitys ''Prumnopitys'' is a genus of conifers belonging to the family Podocarpaceae. The nine recognized species of ''Prumnopitys'' are densely branched, dioecious evergreen trees up to 40 metres in height. Etymology The name ''Prumnopitys'' comes ...

'', '' Sundacarpus'', '' Halocarpus'', ''

Parasitaxus ''Parasitaxus usta'' is a rare species of conifer of the family Podocarpaceae, and the sole species of the genus ''Parasitaxus''. It is a woody shrub up to 1.8 m found only in the remote, densely forested areas of New Caledonia, first discover ...

'', ''

Lagarostrobos ''Lagarostrobos franklinii'' is a species of conifer native to the wet southwestern corner of Tasmania, Australia. It is often known as the Huon pine or Macquarie pine, although it is actually a podocarp (Podocarpaceae), not a true pine (Pinace ...

'', '' Manoao'', ''

Saxegothaea ''Saxegothaea'' is a genus comprising a single species, ''Saxegothaea conspicua''. It is a conifer in the podocarp family Podocarpaceae, native to southern South America. It grows in Chile and Argentina from 35° to 46° South latitude; in its nor ...

'', ''

Microcachrys ''Microcachrys tetragona'', the creeping pine or creeping strawberry pine, is a species of dioecious conifer belonging to the podocarp family (Podocarpaceae).Christopher N. Page. 1990. "Podocarpaceae" pages 332-346. In: Klaus Kubitzki (general ...

'', ''

Pherosphaera ''Pherosphaera'' is a genus of conifers belonging to the family Podocarpaceae. Its native range is Southeastern Australia. Both species are evergreen shrubs. They are dioecious, with male and female flowers on separate plants. Species Specie ...

'', ''

Acmopyle ''Acmopyle'' is a genus of conifers belonging to the podocarp family, Podocarpaceae. The genus includes two species of evergreen small to tall well-branched trees and large trees. ''Acmopyle'' is limited to two species, '' A. pancheri'', endemic ...

'', '' Dacrycarpus'', '' Dacrydium'', ''

Falcatifolium ''Falcatifolium'' is a genus of conifers of the family Podocarpaceae. The genus includes evergreen dioecious shrubs and large trees of up to . Five species are presently recognized. The genus was first described by de Laubenfels in 1969, and ...

'', ''

Retrophyllum ''Retrophyllum'' is a genus of conifers in the family Podocarpaceae.Christopher N. Page. 1990. "Podocarpaceae" pages 332-346. In: Klaus Kubitzki (general editor); Karl U. Kramer and Peter S. Green (volume editors) ''The Families and Genera of Vas ...

'', '' Nageia'', ''

Afrocarpus ''Afrocarpus'' is a genus of conifers of the family Podocarpaceae. Two to six species are recognized. They are evergreen trees native to Africa. ''Afrocarpus'' was designated a genus in 1989, when several species formerly classified in ''Podocarp ...

'', '' Podocarpus'' *Order Cupressales **Family

Sciadopityaceae ''Sciadopitys verticillata'', the or Japanese umbrella-pine, is a unique conifer endemic to Japan. It is the sole member of the family Sciadopityaceae and genus ''Sciadopitys'', a living fossil with no close relatives. The oldest fossils of ''S ...

: ''

Sciadopitys ''Sciadopitys verticillata'', the or Japanese umbrella-pine, is a unique conifer endemic to Japan. It is the sole member of the family Sciadopityaceae and genus ''Sciadopitys'', a living fossil with no close relatives. The oldest fossils of ''S ...

'' **Family

: '' Cunninghamia'', '' Taiwania'', '' Athrotaxis'', '' Metasequoia'', '' Sequoia'', '' Sequoiadendron'', '' Cryptomeria'', '' Glyptostrobus'', ''

Taxodium ''Taxodium'' is a genus of one to three species (depending on taxonomic opinion) of extremely flood-tolerant conifers in the cypress family, Cupressaceae. The generic name is derived from the Latin word ''taxus'', meaning " yew", and the Greek ...

'', ''

Papuacedrus ''Papuacedrus papuana'' is a species in the conifer family Cupressaceae, the sole species in the genus ''Papuacedrus''. Some botanists do not consider this species as forming a distinct genus, but include it in the related genus '' Libocedrus''. ...

'', ''

Austrocedrus ''Austrocedrus'' is a genus of conifer belonging to the cypress family ( Cupressaceae). It has only one species, ''Austrocedrus chilensis'', native to the Valdivian temperate rain forests and the adjacent drier steppe-forests of central-southern ...

'', ''

Libocedrus ''Libocedrus'' is a genus of five species of coniferous trees in the cypress family Cupressaceae, native to New Zealand and New Caledonia. The genus is closely related to the South American genera ''Pilgerodendron'' and '' Austrocedrus'', and ...

'', '' Pilgerodendron'', '' Widdringtonia'', ''

Diselma ''Diselma archeri'' (dwarf pine or Cheshunt pine) is a species of plant of the family Cupressaceae and the sole species in the genus ''Diselma''. It is endemic to the alpine regions of Tasmania's southwest and Central Highlands, on the western ...

'', '' Fitzroya'', ''

Callitris ''Callitris'' is a genus of coniferous trees in the Cupressaceae (cypress family). There are 16 recognized species in the genus, of which 13 are native to Australia and the other three (''C. neocaledonica, C. sulcata'' and ''C. p ...

'', ''

Actinostrobus ''Actinostrobus'' is a genus of coniferous trees in the Cupressaceae (cypress family). Common names include cypress, sandplain-cypress and cypress-pine, the last of these shared by the closely related genus '' Callitris''. Species There are th ...

'', ''

Neocallitropsis ''Callitris pancheri'' is a plant species of the family Cupressaceae. It is endemic to New Caledonia, where it occurs in small, scattered population along rivers. It used to be placed in its own genus ''Neocallitropsis'' but molecular phylogene ...

'', '' Thujopsis'', '' Thuja'', '' Fokienia'', ''

Chamaecyparis ''Chamaecyparis'', common names cypress or false cypress (to distinguish it from related cypresses), is a genus of conifers in the cypress family Cupressaceae, native to eastern Asia (Japan and Taiwan) and to the western and eastern margins of th ...

'', ''

Cupressus ''Cupressus'' is one of several genera of evergreen conifers within the family Cupressaceae that have the common name cypress; for the others, see cypress. It is considered a polyphyletic group. Based on genetic and morphological analysis, the ge ...

'', '' Juniperus'', '' Calocedrus'', ''

Tetraclinis ''Tetraclinis'' (also called arar, araar or Sictus tree) is a genus of evergreen coniferous trees in the cypress family Cupressaceae, containing only one species, ''Tetraclinis articulata'', also known as Thuja articulata,Platycladus'', ''

Microbiota Microbiota are the range of microorganisms that may be commensal, symbiotic, or pathogenic found in and on all multicellular organisms, including plants. Microbiota include bacteria, archaea, protists, fungi, and viruses, and have been found t ...

'' **Family Taxaceae: ''

Austrotaxus ''Austrotaxus spicata'', the New Caledonia yew or southern yew, is a species of yew, the sole species in the genus ''Austrotaxus''. It is related to the other yews in the genera ''Taxus'' and ''Pseudotaxus''. It is endemic to New Caledonia, occ ...

'', ''

Pseudotaxus ''Pseudotaxus chienii'', the whiteberry yewThomas, P. & Yang, Y. 2013''Pseudotaxus chienii''.The IUCN Red List of Threatened Species. Version 2015.2. Downloaded on 04 September 2015. (), is a species of plant in the yew family, Taxaceae. It is th ...

'', '' Taxus'', ''

Cephalotaxus ''Cephalotaxus'', commonly called plum yew or cowtail pine, is a genus of conifers comprising 11 species, treated in either the Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense. The genus is endemic to eastern A ...

'', ''

Amentotaxus ''Amentotaxus'' is a genus of conifers (catkin-yews) comprising five species, treated in either the Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense. The genus is endemic to subtropical Southeast Asia, from Ta ...

'', '' Torreya''

Extinct groupings

* Division Pteridospermatophyta * Order Bennettitales ** Family

Cycadeoidaceae Cycadeoidaceae is a family of bennettitalean plants which flourished in the Mesozoic era. Two genera, ''Cycadeoidea'' and ''Monanthesia'', are currently recognised though most species are poorly known. They had a similar morphology to cycads ...

** Family

Williamsoniaceae ''Williamsoniaceae'' is a family within the Bennettitales, an extinct group of seed plants within the Cycadophyta subdivision. Members of this family are believed to have been around two meters tall and with widely serrate leaves along a central s ...

* Order

Erdtmanithecales Erdtmanithecales is an extinct order of gymnosperm plants known from the Mesozoic era. Known remains include pollen organs, seed cones and seeds associated with '' Eucommiidites'' pollen, which is considered diagnostic for the order. The order was ...

*Order

Pentoxylales Pentoxylales is an extinct order of seed plants known from the Jurassic and Early Cretaceous of East Gondwana. Discovery The first specimens belonging to Pentoxylales were reported by Birbal Sahni in 1948 from Jurassic-Cretaceous strata of the ...

*Order

Czekanowskiales Czekanowskiales, also known as Leptostrobales, are an extinct group of seed plants. Members of the family are distinguished by persistent leaves borne on deciduous short shoots, subtended by scale-like leaves. The leaves are highly dissected (div ...

Life cycle

Gymnosperms, like all vascular plants, have a sporophyte-dominant life cycle, which means they spend most of their life cycle with diploid cells, while the gametophyte (gamete-bearing phase) is relatively short-lived. Like all seed plants, they are heterosporous, having two spore types, microspores (male) and megaspores (female) that are typically produced in pollen cones or ovulate cones, respectively. The exception is the females in the cycad genus Cycas, which form a loose structure called megasporophylls instead of cones. As with all heterosporous plants, the gametophytes develop within the spore wall. Pollen grains (microgametophytes) mature from microspores, and ultimately produce sperm cells. Megagametophytes develop from megaspores and are retained within the ovule. Gymnosperms produce multiple

archegonia An archegonium (pl: archegonia), from the ancient Greek ''ἀρχή'' ("beginning") and ''γόνος'' ("offspring"), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female ga ...

, which produce the female gamete. During pollination, pollen grains are physically transferred between plants from the pollen cone to the ovule. Pollen is usually moved by wind or insects. Whole grains enter each ovule through a microscopic gap in the ovule coat ( integument) called the micropyle. The pollen grains mature further inside the ovule and produce sperm cells. Two main modes of fertilization are found in gymnosperms. Cycads and '' Ginkgo'' have

flagellated A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have fro ...

motile sperm that swim directly to the egg inside the ovule, whereas conifers and gnetophytes have sperm with no flagella that are moved along a

pollen tube A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates. Pollen tube elongation is an integral stage in the plant life cycle. The pollen tube acts as a conduit to transport the male gamete cells fro ...

to the egg. After

syngamy Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

(joining of the sperm and egg cell), the zygote develops into an embryo (young sporophyte). More than one embryo is usually initiated in each gymnosperm seed. The mature seed comprises the embryo and the remains of the female gametophyte, which serves as a food supply, and the seed coat.

Genetics

The first published sequenced genome for any gymnosperm was the genome of '' Picea abies'' in 2013.

Uses

Gymnosperms have major economic uses. Pine, fir, spruce, and cedar are all examples of conifers that are used for lumber, paper production, and resin. Some other common uses for gymnosperms are soap,

varnish Varnish is a clear transparent hard protective coating or film. It is not a stain. It usually has a yellowish shade from the manufacturing process and materials used, but it may also be pigmented as desired, and is sold commercially in various ...

nail polish Nail polish (also known as nail varnish or nail enamel) is a lacquer that can be applied to the human fingernail or toenails to decorate and protect the nail plates. The formula has been revised repeatedly to enhance its decorative properties ...

, food, gum, and perfumes.

References

General bibliography

External links

Gymnosperm DatabaseGymnosperms on the Tree of Life
* {{Authority control 01 Extant Late Devonian first appearances