Pinophyta

Pinophyta
Fossil range: Late Carboniferous - Recent
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Trees of a Pinophyta species:
Araucaria heterophylla (Araucariaceae)

Trees of a Pinophyta species:
Araucaria heterophylla (Araucariaceae)
Scientific classification
Kingdom:Plantae
Division:Pinophyta
Class:Pinopsida
Orders & Families


Cordaitales †
Pinales
  Pinaceae - Pine family
  Araucariaceae - Araucaria family
  Podocarpaceae - Yellow-wood family
  Sciadopityaceae - Umbrella-pine family
  Cupressaceae - Cypress family
  Cephalotaxaceae - Plum-yew family
  Taxaceae - Yew family
Vojnovskyales †
Voltziales ?
The conifers, division Pinophyta, also known as division Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being trees with just a few being shrubs. Typical examples of conifers include cedars, cypresses, douglas-firs, firs, junipers, kauris, larches, pines, redwoods, spruces, and yews. Species of conifers can be found growing naturally in almost all parts of the world, and are frequently dominant plants in their habitats, as in the taiga, for example. Conifers are of immense economic value, primarily for timber and paper production; the wood of conifers is known as softwood. The division contains approximately 700 living species.

Evolution

The earliest Conifers date back to the late Carboniferous (Pennsylvanian) period.

Taxonomy and naming

The division name Pinophyta conforms with the rules of the ICBN, which state (Art 16.1) that the names of higher taxa in plants (above the rank of family) are either formed from the name of an included family, in this case Pinaceae (the pine family), or are descriptive. In the latter case the name for the conifers (at whatever rank is chosen) is Coniferae (Art 16 Ex 2), which is also in widespread use. Older scientific names (no longer allowed) are Coniferophyta and Coniferales.

According to Article 16 of the ICBN such "descriptive botanical names" may be used at any rank above family. Alternatively, it is also possible to use a name formed by replacing the termination -aceae in the name of an included family, preferably Pinaceae, by the appropriate termination. Both are allowed.

This means that if the conifers are regarded to be an order they may be called Coniferae or Pinales (but see also Coniferales); if regarded as a class they may be called Coniferae or Pinopsida; if regarded as a division they may be called Coniferae or Pinophyta.

Commonly the conifers are considered equivalent to the Gymnosperms, particularly in areas with a temperate climate where they may be the only commonly occurring gymnosperms. However, these are two different groupings; conifers are the largest and economically most important component group of the gymnosperms, but nevertheless they comprise only one of the four groups.

The division Pinophyta consists of just one class, Pinopsida, which includes both living and fossil taxa. Subdivision of the living conifers into two or more orders has been proposed from time to time. The most commonly seen in the past was a split into two orders, Taxales (Taxaceae only) and Pinales (the rest), but recent research into DNA sequences suggests that this interpretation leaves the Pinales without Taxales as paraphyletic, and the latter order is no longer regarded as distinct. A more accurate subdivision would be to split the class into three orders, Pinales containing only Pinaceae, Araucariales containing Araucariaceae and Podocarpaceae, and Cupressales containing the remaining families (including Taxaceae), but there has not been any significant support for such a split, with the majority of opinion preferring retention of all the families within a single order Pinales, despite their antiquity and diverse morphology.

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Phylogeny of the Pinophyta based on cladistic analysis of molecular data. Derived from papers by A. Farjon and C. J. Quinn & R. A. Price in the Proceedings of the Fourth International Conifer Conference, Acta Horticulturae 615 (2003)
The conifers are now accepted as comprising six to eight families, with a total of 65-70 genera and 600-650 species. The seven most distinct families are linked in the box above right and phylogenetic diagram left. In other interpretations, the Cephalotaxaceae may be better included within the Taxaceae, and some authors additionally recognise Phyllocladaceae as distinct from Podocarpaceae (in which it is included here). The family Taxodiaceae is here included in family Cupressaceae, but was widely recognised in the past and can still be found in many field guides.

The conifers are an ancient group, with a fossil record extending back about 300 million years to the Paleozoic in the late Carboniferous period; even many of the modern genera are recognisable from fossils 60-120 million years old. Other classes and orders, now long extinct, also occur as fossils, particularly from the late Paleozoic and Mesozoic eras. Fossil conifers included many diverse forms, the most dramatically distinct from modern conifers being some herbaceous conifers with no woody stems. Major fossil orders of conifers or conifer-like plants include the Cordaitales, Vojnovskyales, Voltziales and perhaps also the Czekanowskiales (possibly more closely related to the Ginkgophyta).

Morphology

All living conifers are woody plants, and most are trees, the majority having monopodial growth form (a single, straight trunk with side branches) with strong apical dominance. The size of mature conifers varies from less than one meter, to over 100 metres. The world's tallest, largest, thickest and oldest living things are all conifers. The tallest is a Coast Redwood (Sequoia sempervirens), with a height of 115.2 metres. The largest is a Giant Sequoia (Sequoiadendron giganteum), with a volume 1486.9 cubic metres. The thickest, or tree with the greatest trunk diameter, is a Montezuma Cypress (Taxodium mucronatum), 11.42 metres in diameter. The oldest is a Great Basin Bristlecone Pine (Pinus longaeva), 4,700 years old.

Foliage

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Pinaceae: needle leaves and bud of Coast Douglas-fir (Pseudotsuga menziesii)
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Cupressaceae: scale leaves of Lawson's Cypress (Chamaecyparis lawsoniana); scale in mm
The leaves of many conifers are long, thin and needle-like, but others, including most of the Cupressaceae and some of the Podocarpaceae, have flat, triangular scale-like leaves. Some, notably Agathis in Araucariaceae and Nageia in Podocarpaceae, have broad, flat strap-shaped leaves. In the majority of conifers, the leaves are arranged spirally, exceptions being most of Cupressaceae and one genus in Podocarpaceae, where they are arranged in decussate opposite pairs or whorls of 3 (-4). In many species with spirally arranged leaves, the leaf bases are twisted to present the leaves in a flat plane for maximum light capture (see e.g. photo of Grand Fir Abies grandis). Leaf size varies from 2 mm in many scale-leaved species, up to 400 mm long in the needles of some pines (e.g. Apache Pine Pinus engelmannii). The stomata are in lines or patches on the leaves, and can be closed when it is very dry or cold. The leaves are often dark green in colour which may help absorb a maximum of energy from weak sunshine at high latitudes or under forest canopy shade. Conifers from hotter areas with high sunlight levels (e.g. Turkish Pine Pinus brutia) often have yellower-green leaves, while others (e.g. Blue Spruce Picea pungens) have a very strong glaucous wax bloom to reflect ultraviolet light. In the great majority of genera the leaves are evergreen, usually remaining on the plant for several (2-40) years before falling, but five genera (Larix, Pseudolarix, Glyptostrobus, Metasequoia and Taxodium) are deciduous, shedding the leaves in autumn and leafless through the winter. The seedlings of many conifers, including most of the Cupressaceae, and Pinus in Pinaceae, have a distinct juvenile foliage period where the leaves are different, often markedly so, from the typical adult leaves.

Reproduction

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Pinaceae: cone of a Norway Spruce (Picea abies)
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Pinaceae: pollen cone of a Japanese Larch (Larix kaempferi)
See conifer cones for a more detailed discussion.

Most conifers are monoecious, but some are subdioecious or dioecious; all are wind-pollinated. Conifer seeds develop inside a protective cone called a strobilus (or, very loosely, "pine cones", which technically occur only on pines, not other conifers!). The cones take from four months to three years to reach maturity, and vary in size from 2 mm to 600 mm long. In Pinaceae, Araucariaceae, Sciadopityaceae and most Cupressaceae, the cones are woody, and when mature the scales usually spread open allowing the seeds to fall out and be dispersed by the wind. In some (e.g. firs and cedars), the cones disintegrate to release the seeds, and in others (e.g. the pines that produce pine nuts) the nut-like seeds are dispersed by birds (mainly nutcrackers and jays) which break up the specially adapted softer cones. Ripe cones may remain on the plant for a varied amount of time before falling to the ground; in some fire-adapted pines, the seeds may be stored in closed cones for up to 60-80 years, being released only when a fire kills the parent tree.

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Taxaceae: the fleshy aril which surrounds each seed in the European Yew (Taxus baccata) is a highly modified seed cone scale
In the families Podocarpaceae, Cephalotaxaceae, Taxaceae, and one Cupressaceae genus (Juniperus), the scales are soft, fleshy, sweet and brightly coloured, and are eaten by fruit-eating birds, which then pass the seeds in their droppings. These fleshy scales are (except in Juniperus) known as arils. In some of these conifers (e.g. most Podocarpaceae), the cone consists of several fused scales, while in others (e.g. Taxaceae), the cone is reduced to just one seed scale or (e.g. Cephalotaxaceae) the several scales of a cone develop into individual arils, giving the appearance of a cluster of berries.

The male cones have structures called microsporangia which produce yellowish pollen. Pollen is released and carried by the wind to female cones. Pollen grains from living pinophyte species produce pollen tubes, much like those of angiosperms. When a pollen grain lands near a female gametophyte, it undergoes meiosis and fertilizes the female gametophyte. The resulting zygote develops into an embryo, which along with its surrounding integument, becomes a seed. Eventually the seed may fall to the ground and, if conditions permit, grows into a new plant.

In forestry, the terminology of flowering plants has commonly though inaccurately been applied to cone-bearing trees as well. The male cone and unfertilized female cone are called "male flower" and "female flower", respectively. After fertilization, the female cone is termed "fruit", which undergoes "ripening" (maturation).

Life cycle

  1. To fertilize the ovum, the male cone releases pollen that is carried on the wind to the female cone.
  2. A fertilized female gamete (called a zygote) develops into an embryo.
  3. Along with integument cells surrounding the embryo, a seed develops containing the embryo.
  4. Mature seed drops out of cone onto the ground.
  5. Seed germinates and seedling grows into a mature plant.
  6. When mature, the adult plant produces cones.

Other facts

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Young Longleaf Pine trees
Although the total number of species is relatively small, conifers are of immense ecological importance. They are the dominant plants over huge areas of land, most notably the boreal forests of the northern hemisphere, but also in similar cool climates in mountains further south.

Many conifers have distinctly scented resin, secreted to protect the tree against insect infestation and fungal infection of wounds. Fossilised resin hardens into amber.

External links

Pennsylvanian is an epoch of the Carboniferous period lasting from roughly 325 Ma to 299 Ma (million years ago). As with most other geologic periods, the rock beds that define the period are well identified, but the exact date of the start and end are uncertain by a few million
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Araucaria heterophylla
(Salisb.) Franco

Araucaria heterophylla (synonym A. excelsa) is a distinctive conifer, a member of the ancient and now disjointly distributed family Araucariaceae.
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Araucariaceae
Henkel & W. Hochstetter

Genera

Agathis
Araucaria
Wollemia
Araucarioxylon

The Araucariaceae are a very ancient family of conifers.
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Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
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Plantae
Haeckel, 1866[1]

Divisions

Green algae
  • Chlorophyta
  • Charophyta
Land plants (embryophytes)
  • Non-vascular land plants (bryophytes)

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Pinales

Families

Pinaceae, pine family
Araucariaceae, araucaria family
Podocarpaceae, yellow-wood family
Sciadopityaceae, umbrella-pine family
Cupressaceae, cypress family
Cephalotaxaceae, plum-yew family
Taxaceae, yew family
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Pinaceae
Lindley

Genera

Subfamily Pinoideae
    Pinus - pines (about 115 species)
Subfamily Piceoideae
    Picea - spruces (about 35 species)
Subfamily Laricoideae
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Araucariaceae
Henkel & W. Hochstetter

Genera

Agathis
Araucaria
Wollemia
Araucarioxylon

The Araucariaceae are a very ancient family of conifers.
..... Click the link for more information.
Podocarpaceae
Endl.

Genera

Acmopyle
Afrocarpus
Dacrycarpus
Dacrydium
Falcatifolium
Halocarpus
Lagarostrobos
Lepidothamnus
Manoao
Microcachrys
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Sciadopityaceae
Luerss.

Genus: Sciadopitys
Siebold & Zucc.

Species: S.
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Cupressaceae
Richard ex Bartling

Genera

Actinostrobus - Cypress-pine
Athrotaxis - Tasmanian Cedar Austrocedrus
Callitris - Cypress-pine
Callitropsis - Cypress * (Cupressus)
Calocedrus
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Cephalotaxaceae
Neger

Genera

Amentotaxus
Cephalotaxus
Torreya

The family Cephalotaxaceae
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Taxaceae
S.F. Gray

Genera

Taxaceae sensu stricto
Taxus
Pseudotaxus
Austrotaxus
——
Cephalotaxaceae
Torreya
Amentotaxus
Cephalotaxus
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Conifer may refer to:
  • Pinophyta (conifers), cone-bearing seed plants
  • Conifer, Colorado, an unincorporated town in the United States
  • Conifer High School
  • Conifer Grove, a suburb of Auckland, New Zealand
  • USCGC

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division.

The main plant divisions, in the order in which they probably evolved, are the liverworts (Division Marchantiophyta), the hornworts (Division Anthocerophyta), the mosses (Division Bryophyta), the ferns (Division Filicophyta), the horsetails (Division Sphenophyta),
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A taxon (plural taxa), or taxonomic unit, is a name designating an organism or group of organisms. A taxon is assigned a rank and can be placed at a particular level in a systematic hierarchy reflecting evolutionary
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Plantae
Haeckel, 1866[1]

Divisions

Green algae
  • Chlorophyta
  • Charophyta
Land plants (embryophytes)
  • Non-vascular land plants (bryophytes)

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cone (in formal botanical usage: strobilus, plural strobili) is an organ on plants in the division Pinophyta (conifers) that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds.
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Plantae
Haeckel, 1866[1]

Divisions

Green algae
  • Chlorophyta
  • Charophyta
Land plants (embryophytes)
  • Non-vascular land plants (bryophytes)

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Divisions
  • Non-seed-bearing plants
  • †Rhyniophyta
  • †Zosterophyllophyta
  • Lycopodiophyta

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A woody plant is any vascular plant that has a perennial stem that is above ground and covered by a layer of thickened bark. Woody plants are adapted to survive from one year to the next; the stem supports continued vegetative growth above ground from one year to next.
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tree is a perennial woody plant. It is sometimes defined as a woody plant that attains diameter of 10 cm (30 cm girth) or more at breast height (130 cm above ground).
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A shrub or bush is a horticultural rather than strictly botanical category of woody plant, distinguished from a tree by its multiple stems and lower height, usually less than 5-6 m (15-20 ft) tall.
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Cedrus
Duham.

Species

Cedrus deodara
Cedrus libani
  C. libani var. libani
  C. libani var. stenocoma
  C. libani var.
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Cupressaceae
Richard ex Bartling

Genera

Actinostrobus - Cypress-pine
Athrotaxis - Tasmanian Cedar Austrocedrus
Callitris - Cypress-pine
Callitropsis - Cypress * (Cupressus)
Calocedrus
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Pseudotsuga
Carrière

Species
See text

Douglas-fir is the common name applied to coniferous trees of the genus Pseudotsuga in the family Pinaceae.
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FIR may stand for:
  • FIR FILM IMPACT RECAP directed by trident and hosted by kathi selvakumar on rogers channel 622
  • Finite impulse response, a digital filter type.

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Juniperus
L.

Species
See text

Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae.
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Agathis
Salisb.

Species
See text

The genus Agathis, commonly known as kauri or dammar, forms a relatively small group of 21 species of evergreen trees in the family Araucariaceae, characteristically with very large
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Larix
Miller

Species
About 12; see text

Larches are conifers in the genus Larix, in the family Pinaceae. They are native to much of the cooler temperate northern hemisphere, on lowlands in the far north, and high on mountains
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