The gymnosperms ( ; ) are a group of woody, perennial seed-producing plants, typically lacking the protective outer covering which surrounds the seeds in flowering plants, that include

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 e ...

cycad 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 ...

Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants, assigned to the gymnosperms. The scientific name is also used as the English common name. The order to which the genus belongs, Ginkgoales, first appeared in the Permian, , and ''Ginkgo'' is n ...

, and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in ( and ), and literally means 'naked seeds'. The name is based on the unenclosed condition of their seeds (called

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the sporangium, megasporangium), ...

s in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (

angiosperms Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit. T ...

), which are enclosed within an

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

. Gymnosperm seeds develop either on the surface of scales or

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

, which are often modified to form cones, or on their own as in yew, ''

Torreya ''Torreya'' is a genus of conifers comprising six or seven species placed in the family Taxaceae, though sometimes formerly placed in Cephalotaxaceae. Four species are native to eastern Asia; the other two are native to North America. They a ...

'', and ''

''. The life cycle of a gymnosperm involves

alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of life cycle in plants and algae. In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploi ...

, with 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. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

sporophyte A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spo ...

phase, and a reduced

haploid Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the se ...

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

paleobotany Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments ( pal ...

to refer to (the

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

group of) all non-angiosperm seed plants. In that case, to specify the modern

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

group of gymnosperms, the term Acrogymnospermae is sometimes used. The gymnosperms and

together constitute the

spermatophytes A seed plant or spermatophyte (; New Latin ''spermat-'' and Greek ' (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. la ...

or seed plants. The spermatophytes are subdivided into five

divisions Division may refer to: Mathematics *Division (mathematics), the inverse of multiplication * Division algorithm, a method for computing the result of mathematical division Military *Division (military), a formation typically consisting of 10,000 t ...

, the angiosperms and four divisions of gymnosperms: the Cycadophyta,

Ginkgophyta Ginkgoopsida is a proposed class of gymnosperms defined by Sergei V. Meyen in 1984 to encompass Ginkgoales (which contains the living ''Ginkgo'') alongside a number of extinct seed plant groups, which he considered to be closely related based ...

Gnetophyta Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict ...

, and

Pinophyta 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 ...

(also known as Coniferophyta). Newer classification place the gnetophytes among the conifers. Numerous extinct seed plant groups are recognised including those considered pteridosperms/seed ferns, as well other groups like the Bennettitales. By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes ('' Gnetum'', '' Ephedra'' and ''

Welwitschia ''Welwitschia'' is a monotypic genus of gnetophytes containing only the species ''Welwitschia mirabilis''. It is named after the Austrian botanist Friedrich Welwitsch, who documented the plant in the 1850s. In common use, it is sometimes ref ...

''), and ''

Ginkgo biloba ''Ginkgo biloba'', commonly known as ginkgo or gingko ( ), also known as the maidenhair tree, is a species of gymnosperm tree native to East Asia. It is the last living species in the order Ginkgoales, which first appeared over 290 million year ...

'' (a single living species). About 65% of gymnosperms are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, 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 comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

. Some genera have

ectomycorrhiza An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobio ...

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

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

Diversity and origin

Over 1,000 living species of gymnosperm exist. It was previously widely accepted that the gymnosperms originated in the

Late Carboniferous Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * Late (The 77s album), ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudo ...

period, replacing the

lycopsid Lycopodiopsida is a class of vascular plants also known as lycopsids, lycopods, or lycophytes. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves ...

rainforests of the tropical region, but more recent phylogenetic evidence indicates that they diverged from the ancestors of

during the

Early Carboniferous Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican d ...

. The radiation of gymnosperms during the late Carboniferous appears to have resulted from a whole genome duplication event around . Early characteristics of seed plants are evident in fossil progymnosperms of the late

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

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 that had specialized

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular arthropod mouthparts, mouthparts used for feeding and sucking. In vertebrates, a pr ...

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 Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

) resembled the modern butterflies that arose far later. Zamia integrifolia02

All gymnosperms are

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

woody plant A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to Herbaceous plant, herbaceous plants that die back to t ...

s, Unlike in other extant gymnosperms the soft and highly parenchymatous 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 ...

gymnosperms and compared to angiosperms they occupy fewer

ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of Resource (biology), resources an ...

s, but have evolved both parasites ('' Parasitaxus''),

epiphyte An epiphyte is a plant or plant-like organism that grows on the surface of another 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 epiphyt ...

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 sin ...

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). Most conifers are

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

s. The

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

Cupressaceae Cupressaceae or the cypress family is a family of conifers. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecio ...

and some

Podocarpaceae Podocarpaceae is a large family of mainly southern hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs.James E. Eckenwalder. 2009. ''Conifers of the World''. Portland, Oregon: Timber Pres ...

, have flat, triangular scale-like leaves. '' Agathis'' in Araucariaceae and ''

Nageia ''Nageia'' is a genus of conifers belonging to the podocarp 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 ...

'' in Podocarpaceae have broad, flat strap-shaped leaves.

Cycad 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 ...

s, small palm-like trees, 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 ''Gnetophytes'' and one species of ''

''. The ginkgo or maidenhair trees are tall and have bilobed leaves, while gnetophytes are a diverse groups of plants and shrubs including the horizontally growing

welwitschia ''Welwitschia'' is a monotypic genus of gnetophytes containing only the species ''Welwitschia mirabilis''. It is named after the Austrian botanist Friedrich Welwitsch, who documented the plant in the 1850s. In common use, it is sometimes ref ...

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

spermatophyte A seed plant or spermatophyte (; New Latin ''spermat-'' and Greek ' (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. la ...

s. The wider "Gymnospermae" group includes extinct gymnosperms and is thought to be

. The fossil record of gymnosperms includes many distinctive

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

that do not belong to the four modern groups, including seed-bearing trees that have a somewhat

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

-like vegetative morphology (the so-called "seed ferns" or

pteridosperm Pteridospermatophyta, also called pteridosperms or seed ferns, are a polyphyletic grouping of extinct Spermatophyte, seed-producing plants. The earliest fossil evidence for plants of this type are the Lyginopteridales, lyginopterids of late Devon ...

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

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

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

Bowenia The genus ''Bowenia'' includes two extant taxa, living and two fossil species of cycads in the family Stangeriaceae, sometimes placed in their own family Boweniaceae. They are entirely restricted to Australia. Description The chromosome count i ...

'', '' Macrozamia'', '' Lepidozamia'', ''

Encephalartos ''Encephalartos'' is a genus of cycad native to Africa. Several species of ''Encephalartos'' are commonly referred to as bread trees, bread palms or kaffir bread, since a bread-like starchy food can be prepared from the centre of the stem. The ge ...

'', '' Stangeria'', '' Ceratozamia'', '' Microcycas'', '' Zamia'' Subclass Ginkgoidae * Order

Ginkgoales Ginkgoales are a gymnosperm Order (biology), order containing only one Neontology, extant species: ''Ginkgo biloba'', the ginkgo tree. The order has a long fossil record extending back to the Early Permian around 300 million years ago from fossi ...

** Family

Ginkgoaceae The Ginkgoaceae is a family of gymnosperms which appeared during the Mesozoic Era, of which the only extant representative is ''Ginkgo biloba'', which is for this reason sometimes regarded as a living fossil. Formerly, however, there were several ...

: ''

'' Subclass Gnetidae * Order

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

** 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) s ...

: ''

'' * Order

Gnetales Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three Relict ...

** Family Gnetaceae: '' Gnetum'' * Order Ephedrales ** Family

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

: '' Ephedra'' Subclass Pinidae * Order

Pinales The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers. The distinguishing characteristic is the reproductive structure known as a cone produced by all Pinales. All of the extant conifers, such as Arauca ...

** Family

Pinaceae The Pinaceae (), or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as Cedrus, cedars, firs, Tsuga, hemlocks, Pinyon_pine, piñons, larches, pines and spruces. The family is incl ...

: ''

Cedrus ''Cedrus'', with the common English name cedar, is a genus of coniferous trees in the plant family Pinaceae (subfamily Abietoideae). They are native to the mountains of the western Himalayas and the Mediterranean region, occurring at altitud ...

'', ''

Pinus A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as c ...

'', ''

Cathaya ''Cathaya'' is a genus in the pine family, Pinaceae, with one known living species, ''Cathaya argyrophylla''. In foliage and cone morphology, ''Cathaya'' has been considered a member of the subfamily Laricoideae, closely related to '' Pseudotsu ...

'', ''

Picea A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Northern hemisphere. ''Picea'' is the sole genus ...

'', '' Pseudotsuga'', '' Larix'', '' Pseudolarix'', ''

Tsuga ''Tsuga'' (, from Japanese (), the name of '' Tsuga sieboldii'') is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The English-language common name "hemlock" arose from a perceived similarity in the smell of it ...

'', '' Nothotsuga'', '' Keteleeria'', ''

Abies Firs are evergreen coniferous trees belonging to the genus ''Abies'' () in the family Pinaceae. There are approximately 48–65 extant species, found on mountains throughout much of North and Central America, Eurasia, and North Africa. The genu ...

'' * Order Araucariales ** Family

Araucariaceae Araucariaceae is a Family (biology), family of conifers with three living Genus, genera, ''Araucaria'', ''Agathis'', and ''Wollemia''. While the family's native distribution is now largely confined to the Southern Hemisphere, except for a few spe ...

: ''

Araucaria ''Araucaria'' (; original pronunciation: .ɾawˈka. ɾja is a genus of evergreen coniferous trees in the family Araucariaceae. While today they are largely confined to the Southern Hemisphere, during the Jurassic and Cretaceous they were glo ...

'', ''

Wollemia ''Wollemia'' is a genus of coniferous trees in the family Araucariaceae, endemic to Australia. It represents one of only three living genera in the family, alongside ''Araucaria'' and ''Agathis'' (being more closely related to the latter). The ge ...

'', '' Agathis'' ** Family

: ''

Phyllocladus ''Phyllocladus'', the celery pines, is a small genus of conifers, now usually placed in the family Podocarpaceae.James E. Eckenwalder. 2009. ''Conifers of the World''. Timber Press: Portland, OR, USA. .'' ''Species occur mainly in New Zealand, ...

'', '' Lepidothamnus'', '' Prumnopitys'', '' Sundacarpus'', '' Halocarpus'', '' Parasitaxus'', '' Lagarostrobos'', '' 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 no ...

'', '' Microcachrys'', '' Pherosphaera'', '' Acmopyle'', ''

Dacrycarpus ''Dacrycarpus'' is a genus of conifers belonging to the Family (biology), 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 ...

'', ''

Dacrydium ''Dacrydium'' is a genus of conifers belonging to the podocarp family Podocarpaceae. Sixteen species of evergreen Plant sexuality, dioecious trees and shrubs are presently recognized. The genus was first described by Solander in 1786, and former ...

'', '' Falcatifolium'', '' Retrophyllum'', ''

'', ''

Afrocarpus ''Afrocarpus'' is a genus of conifer of the family Podocarpaceae. Five species are recognized. They are evergreen trees native to Africa. ''Afrocarpus'' was designated a genus in 1989, when several species formerly classified in ''Podocarpus'' an ...

'', ''

Podocarpus ''Podocarpus'' () is a genus of conifers, the most numerous and widely distributed of the podocarp family, the Podocarpaceae. ''Podocarpus'' species are evergreen shrubs or trees, usually from tall, known to reach at times. The cones have ...

'' * Order Cupressales ** Family Sciadopityaceae: ''

Sciadopitys ''Sciadopitys'', commonly called umbrella pines, is a genus of a unique conifers now endemic to Japan. The sole living member of the family Sciadopityaceae is '' Sciadopitys verticillata'', a living fossil. The oldest fossils of ''Sciadopitys'' ...

'' ** Family

: '' Cunninghamia'', '' Taiwania'', '' Athrotaxis'', '' Metasequoia'', '' Sequoia'', ''

Sequoiadendron ''Sequoiadendron'' is a genus of evergreen trees, with three species, only one of which survives to the present: * ''Sequoiadendron giganteum'', extant species, extant, commonly known as wellingtonia, giant redwood and giant sequoia, growing nat ...

'', ''

Cryptomeria ''Cryptomeria'' (literally "hidden parts") is a monotypic genus of conifer in the cypress family Cupressaceae. It includes only one species, ''Cryptomeria japonica'' ( syn. ''Cupressus japonica'' L.f.). It is considered to be endemic to Japan, ...

'', '' 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 name is derived from the Latin word ''taxus'', meaning " yew", and the Greek word ' ...

'', '' Papuacedrus'', '' Austrocedrus'', '' Libocedrus'', '' Pilgerodendron'', ''

Widdringtonia ''Widdringtonia'' is a genus of coniferous trees in the Cupressaceae (Cupressaceae, cypress family). The name was Austrian botanist Stephan Endlicher's way of honouring an early expert on the coniferous forests of Spain, Capt. Samuel Edward Widdr ...

'', '' Diselma'', '' Fitzroya'', '' Callitris'', '' Actinostrobus'', '' Neocallitropsis'', ''

Thujopsis ''Thujopsis'' () is a genus of conifers in the cypress family (Cupressaceae), the sole member of which is ''Thujopsis dolabrata''. It is endemic to Japan, where it is known as ''asunaro'' (). It is similar to the closely related genus '' Thuja'' ...

'', '' Thuja'', ''

Fokienia ''Fokienia'' is a genus of conifer tree belonging to the cypress family. In its characteristics, ''Fokienia'' is intermediate between the genera of '' Chamaecyparis'' and '' Calocedrus''. Genetically ''Fokienia'' is much closer to ''Chamaecypari ...

'', ''

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 o ...

'', ''

Cupressus ''Cupressus'' (common name cypress) is one of several genus, genera of evergreen conifers within the Family (biology), family Cupressaceae; for the others, see cypress. It is considered a Polyphyly, polyphyletic group. Based on genetic and morpho ...

'', ''

Juniperus Junipers are coniferous trees and shrubs in the genus ''Juniperus'' ( ) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south ...

'', '' Calocedrus'', '' Tetraclinis'', '' Platycladus'', ''

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

'' ** Family

Taxaceae Taxaceae (), commonly called the yew family, is a coniferous family (biology), family which includes six Extant taxon, extant and two extinct genera, and about 30 species of plants, or in older interpretations three genera and 7 to 12 species. ...

: '' Austrotaxus'', '' Pseudotaxus'', ''

Taxus ''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. Yews occur around the globe in temperate zones of the northern hemisphere, northernmost in Norway and southernmost in the South Celebes. Some populations ex ...

'', '' Cephalotaxus'', ''

Amentotaxus ''Amentotaxus'' is a genus of Pinophyta, 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 (ecology), endemic to subtr ...

'', ''

Extinct groupings

* Order Cordaitales * Order Calamopityales * Order Callistophytales * Order Caytoniales * Order Gigantopteridales * Order Glossopteridales * Order

Lyginopteridales The Lyginopteridales are an extinct group of seed plants known from the Paleozoic. They were the first plant fossils to be described as Pteridospermatophyta, pteridosperms (a polyphyletic group sometimes referred to as "seed ferns") and, thus, th ...

* Order Medullosales * Order Peltaspermales * Order Corystospermales (also known as Umkomasiales) * Order Czekanowskiales * Order Bennettitales (cycadeoids) * Order Erdtmanithecales * Order Pentoxylales * Order Czekanowskiales * Order Petriellales

Life cycle

Gymnosperms, like all

vascular plants Vascular plants (), also called tracheophytes (, ) or collectively tracheophyta (; ), are plants that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue ( ...

, have a sporophyte-dominant life cycle, which means they spend most of their life cycle with diploid cells, while the

(gamete-bearing phase) is relatively short-lived. Like all seed plants, they are heterosporous, having two spore types,

microspore Microspores are land plant spores that develop into male gametophytes, whereas megaspores develop into female gametophytes. The male gametophyte gives rise to sperm cells, which are used for fertilization of an egg cell to form a zygote. Megaspo ...

s (male) produced in microsporangium and

megaspore Megaspores, also called macrospores, are a type of spore that is present in heterosporous plants. These plants have two spore types, megaspores and microspores. Generally speaking, the megaspore, or large spore, germinates into a female gametoph ...

s (female) produced in megasporangium that are typically present in pollen cones or ovulate cones respectively. The microsporangium is carried by microsporophyll (modified leaf) and seeds are carried by ovuliferous scales in the male and female 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, which produce the female gametes. 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 In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, Exoskeleton, shell, germ or Peel (fruit), rind. Etymology The term is derived from ''integumentum'', which is Latin for "a coverin ...

) 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 ''

'' have flagellated 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 fr ...

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 zygote and initiate its development into a new individual organism or of ...

(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

, which serves as a food supply, and the

seed coat In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the ...

. Gymnosperms ordinarily reproduce by

sexual reproduction Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote tha ...

, and only rarely express parthenogenesis.Hörandl E. Apomixis and the paradox of sex in plants. Ann Bot. 2024 Mar 18:mcae044. doi: 10.1093/aob/mcae044. Epub ahead of print. PMID 38497809 Sexual reproduction in gymnosperms appears to be required for maintaining long-term

genomic Genomics is an interdisciplinary field of molecular biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, ...

integrity.

Meiosis Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...

in sexual land plants provides a direct mechanism for repairing DNA in reproductive tissues. The likely primary benefit of cross-pollination in gymnosperms, as in other eukaryotes, is that it allows the avoidance of inbreeding depression caused by the presence of recessive deleterious mutations.

Genetics

The first published sequenced genome for any gymnosperm was the genome of ''

Picea abies ''Picea abies'', the Norway spruce or European spruce, is a species of spruce native to Northern Europe, Northern, Central Europe, Central and Eastern Europe. It has branchlets that typically hang downwards, and the largest cones of any spruce, ...

'' in 2013.

Uses

Gymnosperms have major economic uses. Some, such as pine, fir, spruce, and cedar, are used for

lumber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...

, paper production, and resin. Some other common uses for gymnosperms are

soap Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...

varnish Varnish is a clear Transparency (optics), transparent hard protective coating or film. It is not to be confused with wood stain. It usually has a yellowish shade due to the manufacturing process and materials used, but it may also be pigmente ...

nail polish Nail polish (also known as nail varnish in British English or nail enamel) is a lacquer that can be applied to the human Nail (anatomy), fingernails or toenails to decorate and protect the nail plates. The formula has been revised repeatedly t ...

, food, gum, and

perfume Perfume (, ) is a mixture of fragrance, fragrant essential oils or aroma compounds (fragrances), Fixative (perfumery), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agre ...

References

General bibliography

External links

Gymnosperm Database

Gymnosperms on the Tree of Life
* * Christopher Nigel Page (2023).The Evolution of Arborescent Gymnosperms.

Cambridge University Press Cambridge University Press was the university press of the University of Cambridge. Granted a letters patent by King Henry VIII in 1534, it was the oldest university press in the world. Cambridge University Press merged with Cambridge Assessme ...

. . 2 volumes (volume one on the conifers of the Northern hemisphere and volume 2 on the conifers of the southern hemisphere). {{Authority control 01 Extant Late Devonian first appearances