Pine family

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Pine family
Forest pine (Pinus sylvestris)

Forest pine ( Pinus sylvestris )

Systematics
Empire : Plants (Plantae)
Department : Vascular plants (tracheophyta)
Subdivision : Seed plants (Spermatophytina)
Class : Coniferopsida
Order : Conifers (Coniferales)
Family : Pine family
Scientific name
Pinaceae
Blast ex F.Rudolphi

The pine family (Pinaceae) form a plant family in the order of the conifers (Coniferales). Many species are important as suppliers of wood and pulp . Some species are used as ornamental plants . Many species shape important plant communities.

description

Forest pine ( Pinus sylvestris )

Vegetative characteristics

With the exception of the deciduous larch ( Larix ) and the golden larch ( Pseudolarix amabilis ), the species of the pine family are evergreen trees ; they rarely grow like shrubs . They contain resin and have an aromatic smell. The bark can be smooth, scaly or furrowed depending on the species.

There are mostly woody roots and fiber roots. The lignified roots usually end in unwooded , ectomycorrhizal , fine roots that are renewed after a year at the latest.

The needle-shaped leaves are arranged in a spiral or tuft. The leaves are in the subfamily Abietoideae with the genera fir ( Abies ), spruce ( Picea ) and Douglas fir ( Pseudotsuga ) on long shoots , in the subfamily Laricoideae with the genera larch ( Larix ) and cedar ( Cedrus ) on short or long shoots of the subfamily Pinoideae with the only genus pines ( Pinus ) only in the youth stage on long shoots, then only on short shoots .

The largest known tree specimens of the family are Douglas firs such as the " Red Creek Fir " ( Pseudotsuga menziesii ) with a stature height of 73.8 meters with a trunk diameter BHD of 4.02 meters on Vancouver Island , where the second tallest tree, known as " Big Lonely Doug "is known (at about 66 meters). Sitka spruces can grow to be similar in size : Picea sitchensis with a height of up to 70 meters and trunk diameters of around 3 meters in the Queets River Valley of the Olympic National Park . The oldest known pine trees, over 4000 years old, are Pinus longaeva .

Cones, flowers and seeds

Male, cone-shaped flower of Picea abies
Female, young cone of Picea abies

All types of the pine family are monoecious and separate sexes ( monoecious ). Male, cone-shaped flowers are formed. The short stalked male flowers on one axis contain many stamens ( microsporophylls ). These carry two pollen sacs ( microsporangia ) on their underside . In the case of pollen , the outer layer (ectexin) often comes off in two places and forms two air sacs. The pollen is produced in very large quantities and spread by the wind ( wind pollination ). In the pine family, ripe pollen consists of four cells: two prothallium cells , one pollen tube cell and one generative cell. After pollination , the pollen tube cell grows and the generative cell forms a stem cell and two sperm cells .

The female cones are the inflorescences of angiosperms homologous . The female cone consists of woody seed scales , at the base of which there are two ovules directed towards the base . Each seed scale lies above a more or less free cover scale , which, according to Rudolf Florin, is interpreted as a bract . Accordingly, a single seed scale would have to be homologated as a modified short shoot . The pine plants form cones in which the seeds also ripen. With many pine species there is a whole year between pollination and fertilization , often the female megaspore is not even formed at the beginning, whereas with the spruce, pollination and seed maturity take place in one vegetation period . Two seeds are formed per cone scale. The seeds often have a wing, in some Pinus species it is only rudimentary and cannot be seen with the naked eye.

There are (often up to 24) is usually 2 to 15 cotyledons ( cotyledons formed).

The number of chromosomes is almost always 2n = 24.

Systematics, distribution and history of development

Lebanon cedar ( Cedrus libani )
Aleppo pine ( Pinus halepensis )
Keteleeria davidiana
European larch ( Larix decidua )

From the Cretaceous , there are fossils of Pinaceae. Most of the genera originated in the Early Tertiary in the higher latitudes and upper altitudes of the North American continent.

The main distribution area is the northern hemisphere . The total distribution area extends south to the Caribbean islands , Central America , Japan , China , Indonesia (a species, Pinus merkusii crosses the equator in Sumatra ), the Himalayas and North Africa . There are ten genera with about 108 species (introduced and native) in China; There are six genera and about 66 species in North America, of which two species have been introduced.

Species of the Pinaceae dominate the vegetation of large areas. In North America, they dominate the forests of the boreal and Pacific regions, the western mountain ranges, and the southeast coastal plains. Some species (for example Pinus radiata in Sub-Saharan Africa , South America , New Zealand and Australia ) are grown by humans in forests for wood production in large areas of the world .

The pine family (Pinaceae) is divided into four subfamilies and comprises eleven genera and about 230 species :

  • Subfamily Abietoideae Sweet : The cones are on long shoots. With six genera:
    • Firs ( Abies Mill. ): With about 51 species.
    • Cedars ( Cedrus Trew ): With three kinds.
    • Keteleeria Carrière : With three types.
    • Nothotsuga Hu ex CNPage : Is a monotypic genus with the only species:
    • Hemlocks ( Tsuga (Endl.) Carrière ), also called hemlocks: With eight species.
    • Pseudolarix Gordon : is a monotypical genus with the only species:
  • Subfamily Laricoideae (Rendle) Pilg. & Melch. : The cones are on short shoots. With three genera:
    • Larch ( Larix Mill. ): With about 10 species.
    • Cathaya Chun & Kuang : Is a monotypical genus with the only species:
    • Douglas firs ( Pseudotsuga Carrière ): With about four kinds.
  • Subfamily Piceoideae Frankis : With the only genus:
    • Spruces ( Picea A.Dietr. ): With 33 to 35 species.
  • Subfamily Pinoideae : The cones are on long shoots. With the only genus:
    • Pine ( Pinus L. ): With about 111 species.

A synonym for Pinaceae Lindl. is Abietaceae Gray .

use

Many species of the Pinaceae provide most of the softwood used in the world. Their wood is used in shipbuilding. They supply the raw materials for pulp and the chemical and pharmaceutical industries ( essential oils ). The seeds of some types of pinus are eaten (German pine nuts, Spanish piñon or pignolias).

Many species and their varieties are used as ornamental plants in parks and gardens; especially in the temperate zones. Many species are important forest trees . They are planted as wind protection, as protection against erosion (mountains) and during reforestation measures.

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literature

Individual evidence

  1. ↑ "Red Creek Fir"
  2. ↑ BA LePage: The evolution, biogeography and palaeoecology of the Pinaceae based on fossil and extant representatives. in Acta Horticulturae , Volume 615, 2003, pp. 29-52
  3. ↑ Michael P. Frankis: Generic Inter-Relationships in Pinaceae , in Notes Royal Botanical Garden Edinburgh , 1988, 45 (3), pp. 527-548: Online system and exact description with detailed sketches of the plant parts of the genera. (engl.)
  4. ↑ a b Christopher J. Earle, Michael P. Frankis: Pinaceae at The Gymnosperm Database, 2019. (Engl.)
  5. ↑ Entries on Pinaceae in Plants For A Future

Web links

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