Pinophyta

The Pinophyta, also known as Coniferophyta or Coniferae, or commonly as conifers, are a division of vascular land plants containing a single extant class, Pinopsida. They are gymnosperms, cone-bearing seed plants. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.[1] As of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, and 629 living species.[2]

Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere,[1] but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations. The narrow conical shape of northern conifers, and their downward-drooping limbs, help them shed snow. Many of them seasonally alter their biochemistry to make them more resistant to freezing. While tropical rainforests have more biodiversity and turnover, the immense conifer forests of the world represent the largest terrestrial carbon sink. Conifers are of great economic value for softwood lumber and paper production.[1]

Pinophyta
Temporal range: CarboniferousPresent
Snowfield Peak 8648s
Conifer forests, though comprising few species, cover vast areas, as in this forest in the Cascade Range of western North America.
Scientific classification
Kingdom: Plantae
Clade: Spermatophytes
Division: Pinophyta
Class: Pinopsida
Orders and families
Synonyms
  • Coniferophyta
  • Coniferae

Evolution

Abies lasiocarpa 5922
The narrow conical shape of northern conifers, and their downward-drooping limbs, help them shed snow.

The earliest conifers in the fossil record date to the late Carboniferous (Pennsylvanian) period (about 300 million years ago),[3] possibly arising from Cordaites, a genus of seed-bearing Gondwanan plants with cone-like fertile structures. Pinophytes, Cycadophytes, and Ginkgophytes all developed at this time.[3] An important adaptation of these gymnosperms was allowing plants to live without being so dependent on water. Other adaptations are pollen (so fertilisation can occur without water) and the seed, which allows the embryo to be transported and developed elsewhere.[3]

Conifers appear to be one of the taxa that benefited from the Permian–Triassic extinction event, and were the dominant land plants of the Mesozoic era. They were overtaken by the flowering plants, which first appeared in the Cretaceous, and became dominant in the Cenozoic era. Conifers were the main food of herbivorous dinosaurs, and their resins and poisons would have given protection against herbivores. Reproductive features of modern conifers had evolved by the end of the Mesozoic era.[4]

Taxonomy and naming

Conifer is a Latin word, a compound of conus (cone) and ferre (to bear), meaning "the one that bears (a) cone(s)".

The division name Pinophyta conforms to the rules of the International Code of Nomenclature for algae, fungi, and plants (ICN), which state (Article 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 (usually the most common and/or representative), in this case Pinaceae (the pine family), or are descriptive. A descriptive name in widespread use for the conifers (at whatever rank is chosen) is Coniferae (Art 16 Ex 2).

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

This means that if conifers are considered a division, they may be called Pinophyta or Coniferae. As a class they may be called Pinopsida or Coniferae. As an order they may be called Pinales or Coniferae or Coniferales.

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 considered 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.

Pinophyta phylogeny
Phylogeny of the Pinophyta based on cladistic analysis of molecular data.[5]

The conifers are now accepted as comprising seven families,[6] with a total of 65–70 genera and 600–630 species (696 accepted names). 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 recognize Phyllocladaceae as distinct from Podocarpaceae (in which it is included here). The family Taxodiaceae is here included in family Cupressaceae, but was widely recognized in the past and can still be found in many field guides. A new classification and linear sequence based on molecular data can be found in an article by Christenhusz et al.[7]

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 recognizable 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).

Pinaceae

Araucariaceae

Podocarpaceae

Sciadopityaceae

Cupressaceae

Cephalotaxaceae

Taxaceae

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. Many conifers have distinctly scented resin, secreted to protect the tree against insect infestation and fungal infection of wounds. Fossilized resin hardens into amber. The size of mature conifers varies from less than one metre, to over 100 metres.[8] The world's tallest, thickest, largest, and oldest living trees are all conifers. The tallest is a Coast Redwood (Sequoia sempervirens), with a height of 115.55 metres (although one Victorian mountain ash, Eucalyptus regnans, allegedly grew to a height of 140 metres, although the exact dimensions were not confirmed). The thickest, or tree with the greatest trunk diameter, is a Montezuma Cypress (Taxodium mucronatum), 11.42 metres in diameter. The largest tree by three-dimensional volume is a Giant Sequoia (Sequoiadendron giganteum), with a volume 1486.9 cubic metres.[9] The smallest is the pygmy pine (Lepidothamnus laxifolius) of New Zealand, which is seldom taller than 30 cm when mature.[10] The oldest is a Great Basin Bristlecone Pine (Pinus longaeva), 4,700 years old.[11]

Foliage

Pseudotsuga menziesii 06280
Pinaceae: needle-like leaves and vegetative buds of Coast Douglas fir (Pseudotsuga menziesii var. menziesii)
Araucaria Leaves
Araucariaceae: Awl-like leaves of Cook Pine (Araucaria columnaris)
Abies grandis 5359
In Abies grandis (grand fir), and many other species with spirally arranged leaves, leaf bases are twisted to flatten their arrangement and maximize light capture.
C lawsoniana Lge
Cupressaceae: scale leaves of Lawson's Cypress (Chamaecyparis lawsoniana); scale in mm

Since most conifers are evergreens,[1] the leaves of many conifers are long, thin and have a needle-like appearance, 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. Others such as Araucaria columnaris have leaves that are awl-shaped. 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, such as Abies grandis (pictured), the leaf bases are twisted to present the leaves in a very flat plane for maximum light capture. 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.[1] 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.

Tree ring structure

Report on the relation of railroads to forest supplies and forestry - together with appendices on the structure of some timber ties, their behavior, and the cause of their decay in the road bed, on (14755970324)
The internal structure of conifer

Tree rings are records of the influence of environmental conditions, their anatomical characteristics record growth rate changes produced by these changing conditions. The microscopic structure of conifer wood consists of two types of cells: parenchyma, which have an oval or polyhedral shape with approximately identical dimensions in three directions, and strongly elongated tracheids. Tracheids make up more than 90% of timber volume. The tracheids of earlywood formed at the beginning of a growing season have large radial sizes and smaller, thinner cell walls. Then, the first tracheids of the transition zone are formed, where the radial size of cells and thickness of their cell walls changes considerably. Finally, the latewood tracheids are formed, with small radial sizes and greater cell wall thickness. This is the basic pattern of the internal cel structure of conifer tree rings.[12]

Reproduction

Most conifers are monoecious, but some are subdioecious or dioecious; all are wind-pollinated. Conifer seeds develop inside a protective cone called a strobilus. 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.

In the families Podocarpaceae, Cephalotaxaceae, Taxaceae, and one Cupressaceae genus (Juniperus), the scales are soft, fleshy, sweet and brightly colored, 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 that produce yellowish pollen through meiosis. 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. The gymnosperm male gametophytes (pollen grains) are carried by wind to a female cone and are drawn into a tiny opening on the ovule called the micropyle. It is within the ovule that pollen-germination occurs. From here, a pollen tube seeks out the female gametophyte, which contains archegonia each with an egg, and if successful, fertilization occurs. The resulting zygote develops into an embryo, which along with the female gametophyte (nutritional material for the growing embryo) and its surrounding integument, becomes a seed. Eventually the seed may fall to the ground and, if conditions permit, grow 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).

It was found recently that the pollen of conifers transfers the mitochondrial organelles to the embryo, a sort of meiotic drive that perhaps explains why Pinus and other conifers are so productive, and perhaps also has bearing on (observed?) sex-ratio bias[13]

Abies lasiocarpa 6972

Pinaceae: unopened female cones of subalpine fir (Abies lasiocarpa)

Taxus baccata MHNT

Taxaceae: the fleshy aril that surrounds each seed in the European Yew (Taxus baccata) is a highly modified seed cone scale

Immature fir cone

Pinaceae: pollen cone of a Japanese Larch (Larix kaempferi)

Life cycle

Conifers are heterosporous, generating two different types of spores: male microspores and female megaspores. These spores develop on separate male and female sporophylls on separate male and female cones. In the male cones, microspores are produced from microsporocytes by meiosis. The microspores develop into pollen grains, which are male gametophytes. Large amounts of pollen are released and carried by the wind. Some pollen grains will land on a female cone for pollination. The generative cell in the pollen grain divides into two haploid sperm cells by mitosis leading to the development of the pollen tube. At fertilization, one of the sperm cells unites its haploid nucleus with the haploid nucleus of an egg cell. The female cone develops two ovules, each of which contains haploid megaspores. A megasporocyte is divided by meiosis in each ovule. Each winged pollen grain is a four celled male gametophyte. Three of the four cells break down leaving only a single surviving cell which will develop into a female multicellular gametophyte. The female gametophytes grow to produce two or more archegonia, each of which contains an egg. Upon fertilization, the diploid egg will give rise to the embryo, and a seed is produced. The female cone then opens, releasing the seeds which grow to a young seedling.

  1. To fertilize the ovum, the male cone releases pollen that is carried on the wind to the female cone. This is pollination. (Male and female cones usually occur on the same plant.)
  2. The pollen fertilizes the female gamete (located in the female cone). Fertilization in some species does not occur until 15 months after pollination.[14]
  3. A fertilized female gamete (called a zygote) develops into an embryo.
  4. A seed develops which contains the embryo. The seed also contains the integument cells surrounding the embryo. This is an evolutionary characteristic of the Spermatophyta.
  5. Mature seed drops out of cone onto the ground.
  6. Seed germinates and seedling grows into a mature plant.
  7. When the plant is mature, it produces cones and the cycle continues.

Female reproductive cycles

Conifer reproduction is synchronous with seasonal changes in temperate zones. Reproductive development slows to a halt during each winter season, and then resumes each spring. The male strobilus development is completed in a single year. Conifers are classified by three reproductive cycles, namely; 1-, 2-, or 3- . The cycles refers to the completion of female strobilus development from initiation to seed maturation. All three types or reproductive cycles have a long gap in between pollination and fertilization.

One year reproductive cycle:The genera includes Abies, Picea, Cedrus, Pseudotsuga, Tsuga, Keteleeria (Pinaceae) and Cupressus, Thuja, Cryptomeria, Cunninghamia and Sequoia (Cupressaceae). Female strobili are initiated in late summer or fall in a year, then they overwinter. Female strobili emerge followed by pollination in the following spring . Fertilization takes place in summer of the following year, only 3–4 months after pollination. Cones mature and seeds are then shed by the end of that same year. Pollination and fertilization occurs in a single growing season.[15]

Two-year reproductive cycle:The genera includes Widdringtonia, Sequoiadendron (Cupressaceae) and most species of Pinus. Female strobilus initials are formed in late summer or fall then overwinter. It emerges and receives pollen in the first year spring and become conelets. The conelet goes through another winter rest and in the spring of the 2nd year. The Archegonia form in the conelet and fertilization of the archegonia occurs by early summer of the 2nd year, so the pollination-fertilization interval exceeds a year. After fertilization, the conelet is considered an immature cone. Maturation occurs by autumn of the 2nd year, at which time seeds are shed. In summary, the 1-year and the 2-year cycles differ mainly in the duration of the pollination- fertilization interval.[15]

Three-year reproductive cycle: Three of the conifer species are pine species (Pinus pinea, Pinus leiophylla, Pinus torreyana) which have pollination and fertilization events separated by a 2-year interval. Female strobili initiated during late summer or autumn in a year, then overwinter until the following spring. Female strobili emerge then pollination occurs in spring of the 2nd year then the pollinated strobili become conelets in same year (i.e. the second year). The female gametophytes in the conelet develop so slowly that the megaspore does not go through free-nuclear divisions until autumn of the 3rd year. The conelet then overwinters again in the free-nuclear female gametophyte stage. Fertilization takes place by early summer of the 4th year and seeds mature in the cones by autumn of the 4th year.[15]

Tree development

The growth and form of a forest tree are the result of activity in the primary and secondary meristems, influenced by the distribution of photosynthate from its needles and the hormonal gradients controlled by the apical meristems (Fraser et al. 1964).[16] External factors also influence growth and form.

Fraser recorded the development of a single white spruce tree from 1926 to 1961. Apical growth of the stem was slow from 1926 through 1936 when the tree was competing with herbs and shrubs and probably shaded by larger trees. Lateral branches began to show reduced growth and some were no longer in evidence on the 36-year-old tree. Apical growth totalling about 340 m, 370 m, 420 m, 450 m, 500 m, 600 m, and 600 m was made by the tree in the years 1955 through 1961, respectively. The total number of needles of all ages present on the 36-year-old tree in 1961 was 5.25 million weighing 14.25 kg. In 1961, needles as old as 13 years remained on the tree.The ash weight of needles increased progressively with age from about 4% in first-year needles in 1961 to about 8% in needles 10 years old. In discussing the data obtained from the one 11 m tall white spruce, Fraser et al. (1964)[16] speculated that if the photosynthate used in making apical growth in 1961 was manufactured the previous year, then the 4 million needles that were produced up to 1960 manufactured food for about 600,000 mm of apical growth or 730 g dry weight, over 12 million mm3 of wood for the 1961 annual ring, plus 1 million new needles, in addition to new tissue in branches, bark, and roots in 1960. Added to this would be the photosynthate to produce energy to sustain respiration over this period, an amount estimated to be about 10% of the total annual photosynthate production of a young healthy tree. On this basis, one needle produced food for about 0.19 mg dry weight of apical growth, 3 mm3 wood, one-quarter of a new needle, plus an unknown amount of branch wood, bark and roots.

The order of priority of photosynthate distribution is probably: first to apical growth and new needle formation, then to buds for the next year's growth, with the cambium in the older parts of the branches receiving sustenance last. In the white spruce studied by Fraser et al. (1964),[16] the needles constituted 17.5% of the over-day weight. Undoubtedly, the proportions change with time.

Seed dispersal mechanism

Wind and animals dispersals are two major mechanisms involved in the dispersal of conifer seeds. Wind bore seed dispersal involves two processes, namely; local neighborhood dispersal (LND) and long- distance dispersal (LDD). Long-distance dispersal distances ranges from 11.9–33.7 kilometres (7.4–20.9 mi) from the source.[17] The bird family, Corvidae is the primary distributor of the conifer seeds. These birds are known to cache 32,000 pine seeds and transport the seeds as far as 12–22 kilometres (7.5–13.7 mi) from the source. The birds store the seeds in the soil at depths of 2–3 centimetres (0.79–1.18 in) under conditions which favor germination.[18]

Invasive species

Prospect Pine Forest, Sydney
A Monterey Pine forest in Sydney, Australia.

A number of conifers originally introduced for forestry have become invasive species in parts of New Zealand, including radiata pine (Pinus radiata), lodgepole pine (P. contorta), Douglas fir (Pseudotsuga mensiezii) and European larch (Larix decidua).[19]

In parts of South Africa, maritime pine (Pinus pinaster), patula pine (P. patula) and radiata pine have been declared invasive species.[20] These wilding conifers are a serious environmental issue causing problems for pastoral farming and for conservation.[19]

Radiata pine was introduced to Australia in the 1870s. It is "the dominant tree species in the Australian plantation estate"[21] – so much so that many Australians are concerned by the resulting loss of native wildlife habitat. The species is widely regarded as an environmental weed across southeastern and southwestern Australia [22] and the removal of individual plants beyond plantations is encouraged.[23]

Predators

At least 20 species of roundheaded borers of the family Cerambycidae feed on the wood of spruce, fir, and hemlock (Rose and Lindquist 1985).[24] Borers rarely bore tunnels in living trees, although when populations are high, adult beetles feed on tender twig bark, and may damage young living trees. One of the most common and widely distributed borer species in North America is the whitespotted sawyer (Monochamus scutellatus). Adults are found in summer on newly fallen or recently felled trees chewing tiny slits in the bark in which they lay eggs. The eggs hatch in about 2 weeks, and the tiny larvae tunnel to the wood and score its surface with their feeding channels. With the onset of cooler weather, they bore into the wood making oval entrance holes and tunnel deeply. Feeding continues the following summer, when larvae occasionally return to the surface of the wood and extend the feeding channels generally in a U-shaped configuration. During this time, small piles of frass extruded by the larvae accumulate under logs. Early in the spring of the second year following egg-laying, the larvae, about 30 mm long, pupate in the tunnel enlargement just below the wood surface. The resulting adults chew their way out in early summer, leaving round exit holes, so completing the usual 2-year life cycle.

2016.04.12 18.14.33 DSC03322 - Flickr - andrey zharkikh
Globosa, a cultivar of Pinus sylvestris, a northern European species, in the North American Red Butte Garden

Cultivation

Conifers – notably Abies (fir), Cedrus, Chamaecyparis lawsoniana (Lawson's cypress), Cupressus (cypress), juniper, Picea (spruce), Pinus (pine), Taxus (yew), Thuja (cedar) – have been the subject of selection for ornamental purposes (for more information see the silviculture page). Plants with unusual growth habits, sizes, and colours are propagated and planted in parks and gardens throughout the world.[25]

Conditions for growth

Conifers can absorb nitrogen in either the ammonium (NH4+) or nitrate (NO3) form, but the forms are not physiologically equivalent. Form of nitrogen affected both the total amount and relative composition of the soluble nitrogen in white spruce tissues (Durzan and Steward 1967).[26] Ammonium nitrogen was shown to foster arginine and amides and lead to a large increase of free guanidine compounds, whereas in leaves nourished by nitrate as the sole source of nitrogen guanidine compounds were less prominent. Durzan and Steward noted that their results, drawn from determinations made in late summer, did not rule out the occurrence of different interim responses at other times of year. Ammonium nitrogen produced significantly heavier (dry weight) seedlings with higher nitrogen content after 5 weeks (McFee and Stone 1968)[27] than did the same amount of nitrate nitrogen. Swan (1960)[28] found the same effect in 105-day-old white spruce.

The general short-term effect of nitrogen fertilization on coniferous seedlings is to stimulate shoot growth more so than root growth (Armson and Carman 1961).[29] Over a longer period, root growth is also stimulated. Many nursery managers were long reluctant to apply nitrogenous fertilizers late in the growing season, for fear of increased danger of frost damage to succulent tissues. A presentation at the North American Forest Tree Nursery Soils Workshop at Syracuse in 1980 provided strong contrary evidence: Bob Eastman, President of the Western Maine Forest Nursery Co. stated that for 15 years he has been successful in avoiding winter “burn” to Norway spruce and white spruce in his nursery operation by fertilizing with 50–80 lb/ac (56–90 kg/ha) nitrogen in September, whereas previously winter burn had been experienced annually, often severely. Eastman also stated that the overwintering storage capacity of stock thus treated was much improved (Eastman 1980).[30]

The concentrations of nutrient in plant tissues depend on many factors, including growing conditions. Interpretation of concentrations determined by analysis is easy only when a nutrient occurs in excessively low or occasionally excessively high concentration. Values are influenced by environmental factors and interactions among the 16 nutrient elements known to be essential to plants, 13 of which are obtained from the soil, including nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, all used in relatively large amounts (Buckman and Brady 1969).[31] Nutrient concentrations in conifers also vary with season, age and kind of tissue sampled, and analytical technique. The ranges of concentrations occurring in well-grown plants provide a useful guide by which to assess the adequacy of particular nutrients, and the ratios among the major nutrients are helpful guides to nutritional imbalances.

Economic importance

The softwood derived from conifers is of great economic value, providing about 45% of the world’s annual lumber production. Other uses of the timber include the production of paper and plastic from chemically treated wood pulp. Some conifers also provide foods such as pine nuts and Juniper berries, the latter used to flavor gin.

References

  1. ^ a b c d e Campbell, Reece, "Phylum Coniferophyta". Biology. 7th. 2005. Print. P. 595
  2. ^ Lott, John N. A; Liu, Jessica C; Pennell, Kelly A; Lesage, Aude; West, M Marcia (2002). "Iron-rich particles and globoids in embryos of seeds from phyla Coniferophyta, Cycadophyta, Gnetophyta, and Ginkgophyta: characteristics of early seed plants". Canadian Journal of Botany. 80 (9): 954–961. doi:10.1139/b02-083.
  3. ^ a b c Henry, R.J.(2005) Plant Diversity and evolution. London: CABI.
  4. ^ Claire G. Williams, 2009, Conifer Reproductive Biology, Springer Science
  5. ^ 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)
  6. ^ "Pinidae (conifers) description – The Gymnosperm Database". Archived from the original on 2016-02-20.
  7. ^ Christenhusz, M.J.M., Reveal, J., Farjon, A., Gardner, M.F., Mill, R.R. & Chase, M.W. (2011) A new classification and linear sequence of extant gymnosperms. Phytotaxa 19: 55–70.
  8. ^ Enright, Neal J. and Robert S. Hill. 1990. Ecology of the southern conifers. Washington, DC: Smithsonian. 342pp.
  9. ^ Vidakovic, Mirko. 1991. Conifers: morphology and variation. Translated from Croatian by Maja Soljan. Croatia: Graficki Zavod Hrvatske
  10. ^ Wassilieff, Maggy. "Conifers". Te Ara – the Encyclopedia of New Zealand updated 1-Mar-09.
  11. ^ Dallimore, William, Albert Bruce Jackson, and S.G. Harrison. 1967. A handbook of Coniferae and Ginkgoaceae, 4th ed. New York: St. Martin's Press. xix, 729 p.
  12. ^ Ledig, F. Thomas; Porterfield, Richard L., 1982, Tree Improvement in Western Conifers: Economic Aspects, Journal of Forestry
  13. ^ .
  14. ^ http://bioserv.fiu.edu/~biolab/labs/1011/Spring%202009/TA%20notes%20and%20pictures/Week%205%20-%20Seed%20Plants.htm
  15. ^ a b c Singh, H. 1978. Embryology of gymnosperms. Berlin, Gebruder Borntraeger.
  16. ^ a b c Fraser, D.A.; Belanger, L.; McGuire, D.; Zdrazil, Z. 1964. Total growth of the aerial parts of a white spruce tree at Chalk River, Ontario, Canada. Can. J. Bot. 42:159–179.
  17. ^ Williams CG, LaDeau SL, Oren R, Katul GG., 2006, Modeling seed dispersal distances: implications for transgenic Pinus taeda, Ecological Applications 16:117–124
  18. ^ Tomback, D. and Y. Linhart, 1990. The evolution of bird-dispersed pines. Evolutionary Ecology 4: 185–219
  19. ^ a b "South Island wilding conifer strategy". Department of Conservation (New Zealand). 2001. Retrieved 2009-04-19.
  20. ^ [1]
  21. ^ "Fauna conservation in Australian plantation forests: a review", May 2007, D.B. Lindenmayer and R.J. Hobbs
  22. ^ "Pinus radiata". keyserver.lucidcentral.org.
  23. ^ "Blue Mountains City Council – Fact Sheets [Retrieved 1 August 2015]".
  24. ^ Rose, A.H.; Lindquist, O.H. 1985. Insects of eastern spruces, fir and, hemlock, revised edition. Gov’t Can., Can. For. Serv., Ottawa, For. Tech. Rep. 23. 159 p. (cited in Coates et al. 1994, cited orig ed 1977)
  25. ^ Farjon, Aljos (2010). A handbook of the world's conifers. Brill Academic Publishers. ISBN 978-9004177185.
  26. ^ Durzan, D.J.; Steward, F.C. 1967. The nitrogen metabolism of Picea glauca (Moench) Voss and Pinus banksiana Lamb. as influenced by mineral nutrition. Can. J. Bot. 45:695–710.
  27. ^ McFee, W.W.; Stone, E.L. 1968. Ammonium and nitrate as nitrogen sources for Pinus radiata and Picea glauca. Soil Sci. Soc. Amer. Proc. 32(6):879–884.
  28. ^ Swan, H.S.D. 1960. The mineral nutrition of Canadian pulpwood species. 1. The influence of nitrogen, phosphorus, potassium and magnesium deficiencies on the growth and development of white spruce, black spruce, jack pine and western hemlock seedlings grown in a controlled environment. Pulp Paper Res. Instit. Can., Montreal QC, Woodlands Res. Index No. 116, Tech. Rep. 168. 66 p.
  29. ^ Armson, K.A.; Carman, R.D. 1961. Forest tree nursery soil management. Ont. Dep. Lands & Forests, Timber Branch, Ottawa ON. 74 p.
  30. ^ Eastman, B. 1980. The Western Maine Forest Nursery Company. pp. 291–295 In Proc. of the North American Forest Tree Nursery Soils Workshop, July 28 – August 1, 1980, Syracuse, New York. Environment Canada, Canadian Forestry Service, USDA For. Serv.
  31. ^ Buckman, H.O.; Brady, N.C. 1969. The Nature and Properties of Soils, 7th ed. Macmillan NY. 653 p.

External links

1986 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1986.

Araucariaceae

Araucariaceae – also known as araucarians – is a very ancient family of coniferous trees. The family achieved its maximum diversity during the Jurassic and Cretaceous periods, when it was distributed almost worldwide.

Most of the Araucariaceae in the Northern Hemisphere vanished in the Cretaceous–Paleogene extinction event, and they are now largely confined to the Southern Hemisphere, except for a few species of Agathis in Southeast Asia.

Centriole

In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells. A bound pair of centrioles, surrounded by a shapeless mass of dense material, called the pericentriolar material (PCM), makes up a structure called a centrosome.Centrioles are present in the cells of most eukaryotes, for example those of animals. However, they are absent from conifers (pinophyta), flowering plants (angiosperms) and most fungi, and are only present in the male gametes of charophytes, bryophytes, seedless vascular plants, cycads, and ginkgo.Centrioles are typically made up of nine sets of short microtubule triplets, arranged in a cylinder. Deviations from this structure include crabs and Drosophila melanogaster embryos, with nine doublets, and Caenorhabditis elegans sperm cells and early embryos, with nine singlets.

The main function of centrioles is to produce cilia during interphase and the aster and the spindle during cell division.

Chionodes continuella

Chionodes continuella is a moth of the Gelechiidae family. It is found from most of Europe (except Ireland, Great Britain, the Iberian Peninsula, Switzerland and most of the Balkan Peninsula), east to Japan. It is also present in most of North America.The wingspan is 10–16 mm. Adults have been recorded on wing from June to August in western Europe.

The larvae feed on Pinophyta species, but have also been recorded on Cladonia species, including Cladonia rangiferina.

Conifer cone

A 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. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity. The name "cone" derives from the fact that the shape in some species resembles a geometric cone. The individual plates of a cone are known as scales.

The male cone (microstrobilus or pollen cone) is structurally similar across all conifers, differing only in small ways (mostly in scale arrangement) from species to species. Extending out from a central axis are microsporophylls (modified leaves). Under each microsporophyll is one or several microsporangia (pollen sacs).

The female cone (megastrobilus, seed cone, or ovulate cone) contains ovules which, when fertilized by pollen, become seeds. The female cone structure varies more markedly between the different conifer families, and is often crucial for the identification of many species of conifers.

Cordaitales

Cordaitales are an extinct order of woody plants that may have been early conifers, or which may have given rise to the conifers (Pinophyta), ginkgos (Ginkgophyta) and cycads (Cycadophyta). They had cone-like reproductive structures reminiscent of those of modern conifers. The Cordaitales appeared during the Carboniferous Period forming large trees that seem to have been particularly abundant on drier ground, in tropical environments. Also, some tall trees but also shrubby and mangrove-like species of Cordaitales seem to have grown in the Carboniferous coal swamps. Cordaitales were also abundant during the Permian, but became less important during the Triassic and died out during the time of the end-Triassic mass extinction. Many Cordiatales had elongated strap-like leaves, resembling some modern-day conifers of the Araucariaceae and Podocarpaceae. Common genera from the Carboniferous include Mesoxylon and Cordaixylon.Other genera are Noeggerathiopsis and Sumaropsis.

Division (biology)

This article discusses categorisations of organisms. For a different meaning in biology, see cell division.Division is a taxonomic rank in biological classification that is used differently in zoology and in botany.

In botany and mycology, division refers to a rank equivalent to phylum. The use of either term is allowed under the International Code of Botanical Nomenclature, and both are commonly used in scientific literature.

The main Divisions of land plants, in the order in which they probably evolved, are the Marchantiophyta (liverworts), Anthocerotophyta (hornworts), Bryophyta (mosses), Filicophyta (ferns), Sphenophyta (horsetails), Cycadophyta (cycads), Ginkgophyta (ginkgo)s, Pinophyta (conifers), Gnetophyta (gnetophytes), and the Magnoliophyta (Angiosperms, flowering plants). The flowering plants now dominate terrestrial ecosystems, comprising 80% of vascular plant species.

In zoology, the term division is applied to an optional rank subordinate to the infraclass and superordinate to the cohort. A widely used classification (e.g. Carroll 1988) recognises teleost fishes as a Division Teleostei within Class Actinopterygii (the ray-finned fishes). Less commonly (as in Milner 1988), living tetrapods are ranked as Divisions Amphibia and Amniota within the clade of vertebrates with fleshy limbs (Sarcopterygii).

Grub am Forst

Grub am Forst is a municipality in the district of Coburg in Bavaria in Germany. It has ca 3,100 residents. The nearest large town is Coburg. The following villages are part of it:

Buscheller

Forsthub

Rohrbach

Roth am Forst

ZeickhornThe municipality's political parties are the CSU, SPD, the Freie Wähler and the Wählervereinigung Gut für Grub.

The coat of arms shows a pinophyta in a valley between two hills. It describes the location of Grub am Forst: a village between two hills (Grub/Grube) which is located near to a forest (Forst/Wald).

Gymnosperm

The gymnosperms, also known as Acrogymnospermae, are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the composite word in Greek: γυμνόσπερμος (γυμνός, gymnos, 'naked' and σπέρμα, sperma, 'seed'), 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. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.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).

Roots in some genera have fungal association with roots in the form of mycorrhiza (Pinus), while in some others (Cycas) small specialised roots called coralloid roots are associated with nitrogen-fixing cyanobacteria.

Juniperus saltuaria

Juniperus saltuaria is a species of conifer in the Cupressaceae family. It is endemic to southern China and Tibet. The trees grow up to 20 metres (66 ft) high.

Kubitzki system

The Kubitzki system is a system of plant taxonomy devised by Klaus Kubitzki, and is the product of an ongoing survey of vascular plants, entitled The Families and Genera of Vascular Plants, and extending to 13 volumes in 2015. The survey, in the form of an encyclopedia, is important as a comprehensive, multivolume treatment of the vascular plants, with keys to and descriptions of all families and genera, mostly by specialists in those groups. The Kubitzki system served as the basis for classification in Mabberley's Plant-Book, a dictionary of the vascular plants. Mabberley states, in his Introduction on page xi of the 2008 edition, that the Kubitzki system "has remained the standard to which other literature is compared".

In ordinal and family arrangements, the classification system in the initial angiosperm volumes closely resembles the Dahlgren system in Monocots and the Cronquist system in Dicots, but later volumes have been influenced by recent molecular phylogenetic studies.

The first volume of the series (Pteridophytes and Gymnosperms) covered lycophytes, monilophytes, and gymnosperms, and was published in 1990. By 2010, there were nine published volumes, covering 39 of the 59 orders of flowering plants that are recognized in the APG III system. The order Saxifragales is covered except for the genus Medusandra, which was transferred to it from Malpighiales in 2009. Volume 10 (2011) covers the family Myrtaceae and the orders Cucurbitales and Sapindales. Volume 11 was published in 2014, and two further volumes in 2015. Volumes 2, and 5–7 address dicotyledons, while volumes 3, 4 and 13 address monocotyledons. Volumes 8–12 deal with eudicots.

Because it is the result of a work in progress, the Kubitzki system is incomplete for those groups of plants that have not yet been covered, and groups that have been completely covered are not revised in light of subsequent knowledge. Since the first volume was published in 1990, a great deal has been learned about plant taxonomy, mostly by phylogenetic analysis of DNA sequences. The classification of ferns has been completely overhauled in that time. And some of the gymnosperm families have been revised.For the flowering plants, the later volumes of the Kubitzki System follows the Angiosperm Phylogeny Group last revised in 2009 (APG III system), except for the recognition of smaller families. (For a complete listing of all volumes, see Klaus Kubitzki)

List of coniferous plants of Montana

There are at least 20 species of Gymnosperms or Coniferous plants in Montana. The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. 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, Douglas-firs, cypresses, firs, junipers, kauris, larches, pines, hemlocks, redwoods, spruces, and yews. The division contains approximately eight families, 68 genera, and 630 living species.The Ponderosa Pine, a conifer, is the Montana State Tree.

List of tree genera

The major tree genera are listed below by taxonomic family.

List of trees native to New Zealand

New Zealand's long geological isolation means that most of its flora is unique, with many durable hard woods. There is a wide variety of native trees, adapted to all the various micro-climates in New Zealand. The native bush (forest) ranges from the subtropical kauri forests of the northern North Island, temperate rainforests of the West Coast, the alpine forests of the Southern Alps and Fiordland to the coastal forests of the Abel Tasman National Park and the Catlins.

In the early period of British colonisation, many New Zealand trees were known by names derived from the names of unrelated European trees, but more recently the trend has been to adopt the native Māori language names into English. For a listing in order of Māori name, with species names for most, see the Flora of New Zealand list of vernacular names.

The New Zealand Plant Conservation Network has published a list of New Zealand indigenous vascular plants including all 574 native trees and shrubs. This list also identifies which trees are endemic to New Zealand and which are threatened with extinction.

Pinales

The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers. This order used to be known as the Coniferales.The distinguishing characteristic is the reproductive structure known as a cone produced by all Pinales. All of the extant conifers, such as cedar, celery-pine, cypress, fir, juniper, larch, pine, redwood, spruce, and yew, are included here. Some fossil conifers, however, belong to other distinct orders within the division Pinophyta.

The yews had been separated into a distinct order of their own (Taxales), but genetic evidence indicates yews are monophyletic with other conifers and they are now included in the Pinales.

The families included are the Araucariaceae, Cupressaceae, Pinaceae, Podocarpaceae, Sciadopityaceae, and Taxaceae.

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 subclass is equivalent to the division Pinophyta and class Pinopsida of previous treatments.

Spermatophyte

The spermatophytes, also known as phanerogams (taxon Phanerogamae) or phaenogams (taxon Phaenogamae), comprise those plants that produce seeds, hence the alternative name seed plants. They are a subset of the embryophytes or land plants. The term phanerogams or phanerogamae is derived from the Greek φανερός, phanerós meaning "visible", in contrast to the cryptogamae from Greek κρυπτός kryptós = "hidden" together with the suffix γαμέω, gameein, "to marry". These terms distinguished those plants with hidden sexual organs (cryptogamae) from those with visible sexual organs (phanerogamae).

Taxales

The plant order Taxales was until recently treated as a distinct order in the division Pinophyta, class Pinopsida, and included only those species in the family Taxaceae, known commonly as yews. Under this interpretation, all other conifers were classified separately in the order Pinales. Recent genetic and micromorphological studies, however, have shown the Taxaceae are closely related to the other conifers, particularly so to the family Cephalotaxaceae. The order Taxales is therefore no longer recognised as distinct, and the family Taxaceae is now included in the order Cupressales. See Pinophyta for more details.

Thera variata

Thera variata, the spruce carpet, is a moth of the family Geometridae. It is found throughout Europe, North Asia and Japan. The common name spruce carpet is also used when referring to Thera britannica.

The length of the forewings is 13–17 mm. The moth flies in two generations from mid April to mid October [1].

The larva feeds on spruce and other Pinophyta.

Pinophyta families
Rhodophyta
(red algae)
Glaucocystophyta
(glaucophytes)
Viridiplantae
(green algae,
& land plants)
Extant Life phyla/divisions by domain

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