Pinales

Scots pine (Pinus sylvestris ), illustration

The conifers or softwoods ( Coniferales, often Pinales ), also called pine -like, today the largest surviving group of Nacktsamigen plants. Your ovules are not protected by carpels. The sporophylls are often in journals, where it gets its name comes conifers, which translates to " pin carrier " means.

Occurrence

Conifers, there are almost everywhere in the world. However, emphasis is on the temperate regions of the Northern Hemisphere. The focus in the southern hemisphere have the Araucariaceae and Podocarpaceae which, they also provide a number of representatives in the tropics. Cypress family, however, are found on both the southern and the northern hemisphere. In their northern habitats, the conifers are often the dominant plants, for example in the taiga, the boreal forest belt.

Conifers are common pioneer plants growing on soil, the seed plants of other orders provide inadequate growth conditions. On good soils conifers other hand, are often displaced by them. So lacking conifers in the tropical forests of central Africa and the Amazon. In high-altitude tropical rainforests, as found for example in Southeast Asia, conifers come before it.

A particularly high number of species of coniferous plants are found in California, Mexico, China, with the regions of Sichuan and Yunnan, in Osthimalaya, Japan and Taiwan. One of softwood plants particularly rich island is New Caledonia. On volcanic islands such as Hawaii, however, conifers are missing because the seeds of most conifers is spread via wind and Zoochorie and therefore only close to coasts lying islands of volcanic origin, of course, can be colonized. The occurring in the Azores Kurzblättrige juniper is considered the Nadelholzgewächsart that grows in the greatest distance to the nearest coast. Ancestors of this kind came in the digestive tract of birds on the island.

Description

The extant conifers are woody plants, most species are trees. The majority of taxa has a monopodial growth, ie a main stem with side branches. The plant height of full-grown conifers varies from less than one meter to more than one hundred meters. The highest- growing species is the coast redwood (Sequoia sempervirens), with a maximum height of 112.8 meters. The largest volume has a giant sequoia ( Sequoiadendron giganteum), with 1486.9 cubic meters. The thickest needle tree is a related Mexico Mexican cypress (Taxodium mucronatum ) with a trunk diameter of 11.42 meters. The oldest tree is 5062 years old (based on 2012) copy of longevity pine ( Pinus longaeva ). Old Tjikko, a common spruce is, with 9550 years the oldest living individual Klonbaum.

Basically, the crown structure of coniferous trees of the deciduous trees is different. This arises because the branches of coniferous trees are bent towards the tip upwards. From the gradation of the longitudinal extension of the branches arises at least in younger trees a regular conical crown. An umbrella-shaped Abflächung, as occurs for example in pines, arises only in old age.

The wood stands in contrast to the cycads by narrow medullary rays ( " pycnoxyles wood " ) from. Unlike angiosperms Conifers have never tracheae, but only tracheids. Also, the wood is very often rich in resins.

The leaves of most conifers are long, thin and needle- shaped. But there are also other taxa with leaf shapes, including most cypress family ( Cupressaceae ) and the stone Yews ( Podocarpaceae ), they have flat leaves. Some taxa, especially the Kauri ( Agathis ) within the (Araucariaceae ) and Nageia within the Podocarpaceae, have broad, flat leaves. The genus has Phyllocladus instead of leaves flat leaf-like short shoots, called phylloclades. In the majority of conifers, the leaves are spirally arranged around the branches; Exceptions are the Cupressaceae and one genus in Podocarpaceae, where they are arranged in opposite pairs or permanent in three to four in whorls. There are sheet sizes of 2 mm to 400 mm in length. Very long needles are for example Pinus engelmannii characteristic.

The stomata are arranged in lines or clusters on the leaves. They can be closed in cold or very dry weather. The majority of genera the leaves are evergreen and remain on the plant for several ( 2-40 ) years until they fall off. But three genera, namely larch ( Larix), bald cypress (Taxodium ) and dawn redwood ( Metasequoia ) are deciduous; they lose their leaves in the fall and are leafless during the winter. The seedlings of most conifers, including most Cupressaceae, and pine (Pinus ), have young leaves, which differ greatly from the leaves of older plants.

Seeds and cones

Most conifers are monoecious dioecious mostly monoecious, some are dioecious dioecious ( yew and juniper). All are wind pollinated Pinophyta ( anemophilous ).

Pollination is by unbegeißelte sperm cells are transported through a pollen tube to the egg cell ( Siphonogamie ).

The conifer seeds develop in a protective pin it. The pins need to mature four months to three years. They are 2 mm to 600 mm long.

In the Pinaceae, Araucariaceae, Sciadopityaceae and most Cupressaceae, the cones are woody. If the cones are ripe, usually open to the shed and let the seeds fall out, so that they can be dispersed by the wind. A number of species sheds its mature cones in other species remain, however, those on the branches. The latter include, for example, the Monterey pine, are vaulted from renewable wood in the occasional pin.

For the families of the Podocarpaceae and the genus (Juniperus ) of the Cupressaceae are the scales soft, fleshy, sweet and brightly colored. They are eaten by birds, the seeds pass through the digestive tract and are excreted intact again. The juniper species ( Juniperus ) is called colloquially often of berries, berry cones of better, because it is morphologically not to berries. The Cephalotaxaceae and Taxaceae the fruit shed missing, the seeds are surrounded by a fleshy seed coat ( aril ).

System

The class Coniferopsida (or Pinopsida ) included only long the only order Pinales. Today it is often attributed to the order Gnetales, but this classification is not without controversy. Many molecular genetic studies saw the Gnetales as the sister group to Pinaceae.

The extant representatives of Pinales ( exclusive Gnetales ) are:

• (Araucariaceae )
• Head Yews ( Cephalotaxaceae )
• Cypress family ( Cupressaceae )
• (Pinaceae )
• Podocarpus plants ( Podocarpaceae )
• Shields Anne plants ( Sciadopityaceae )
• Yews ( Taxaceae )

Fossil there is a much greater diversity within the conifers. Within the order Pinales there are in addition to the extant families extinct following:

• Palissyaceae
• Cheirolepidiaceae
• Paraucariaceae

The sister - order of Pinales is the only fossil known order Voltziales.

The phylogenetic relationships of the different families of the two orders were reconstructed by Farjon as follows:

Thucydiaceae

Emporiaceae

Ullmanniaceae

Utrechtiaceae

Majonicaceae

Voltziaceae

Podocarpaceae

Phyllocladaceae

Araucariaceae

Pararaucariaceae

Pinaceae

Cephalotaxaceae

Taxaceae

Palissyaceae

Geinitziaceae

Doliostrobaceae

Cupressaceae

Sciadopityaceae

Cheirolepidiaceae

Ferrugliocladaceae

Evolution

The fossil taxa of the division Pinophyta two important groups are mentioned, which Cordaiten and Voltziales. The Cordaiten lived in the Carboniferous and Permian. There were up to 30 meters high, richly branched trees with lanceolate to band-shaped spirally arranged leaves. The male " flowers " were cone- shaped with basal sterile shed leaves and stamens with several pollen sacs. These were in the armpit of bracts on axes that were, in turn, in the axils of leaves. The female flowers were constructed similarly, except that the terminal shed leaves contributed atrope ovules.

The Voltziales (Upper Carboniferous to sub -Jura ) were also trees with nadligen to scale-like leaves. The stamens were stalked and at the end where the pollen sacs were mostly on the axle side facing surface. The female " flowers " had designed as a Deckschuppe Tragblatt, more sterile shed leaves and stalked ovules. Were also as in the extant conifers at the Voltziales the female flowers in compact cones. You are considered the coniferous plants most similar and most closely related group.

From the findings on Voltziales concluded Rudolf Florin that the ovules do not originate from leaves, but constantly axis ( Stachyosporie ) are. In addition, therefore, the seed scales of recent conifers modified (except Taxaceae and Cephalotaxaceae ) short shoots, since leaves have no bracts ( Deckschuppe! ).