Pinus densata
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Pinus densata is an evergreen conifer from the genus of the pines ( Pinus ) with 8 to 14 centimeter long needles and fully grown 4 to 6 centimeter long seed cones. The distribution area is in China, where it occurs in the high mountains at altitudes of 2600 to 4200 meters. There is evidence that it is a natural cross between three other species of pine. It is not endangered and is hardly used for forestry.
description
Habitus
Representatives of the species Pinus densata are trees up to 30 meters high with trunk diameters of up to 1.3 meters. The bark is initially reddish-brown and later dark gray-brown, scaly and divided into irregularly shaped plates with elongated cracks. The branches are spread out and form an egg-shaped-conical, later broad-egg-shaped or open crown. The twigs are stiff, new shoots are bare, rough due to Pulvini , shiny yellowish brown in the first year, reddish brown in the second and third year.
Buds and needles
The winter buds are dull brown, ovate-conical and pointed. The terminal buds are about 15 millimeters long with a diameter of 6 millimeters. The bud scales are pointed and have a white tinted edge. The needles grow in twos or, less often, in threes in initially 10 to 15 millimeters long, later shortening needle sheaths. The needles are straight, 8 to 14 centimeters long and 1 to 1.5 millimeters wide, stiff, somewhat twisted, pointed and dull green. The edges are finely sawn. There are fine stomata lines on each needle side . Three or four resin channels are formed per needle. The needles stay on the tree for three years.
Cones and seeds
The pollen cones grow spirally arranged in groups at the base of new shoots. They are yellowish brown, short-cylindrical, 10 to 18 millimeters long and 3 to 4.5 millimeters wide. The seed cones grow individually or in pairs, sessile or very short stalked, closed, narrowly ovoid and 4 to 6 inches long and open 4 to 7 inches wide. The seed scales are brown, elongated, thinly woody and stiff. The apophysis is clearly raised, 4 to 7 millimeters thick, clearly keeled transversely, more or less rhombic and shiny chocolate-brown in color. The seeds are ovate to elliptical, 4 to 6 millimeters long and light brown to gray-brown. The seed wing is 15 to 20 millimeters long. Pollination takes place in May, the seed cones ripen in October of the second year.
Chromosome number
The number of chromosomes is 2n = 24.
Distribution, location requirements and endangerment
The natural range of Pinus densata is in China in the south of Qinghai , in the west of Sichuan , in the northwest of Yunnan and in the east of Tibet . It grows in the high mountains at heights of 2600 to 4000 meters or even above up to 4200 meters. Over 3000 meters it forms open pure stands, below it it grows together with other pines, such as Pinus armandii and Pinus yunnanensis .
In the Red List of the IUCN is Pinus densata be deemed not at risk ( "Lower Risk / least concern"). However, it should be noted that a reassessment is pending.
Systematics and research history
Pinus densata is a species of the genus of pines ( Pinus ), in which it is assigned to the subgenus Pinus , section Pinus and subsection Pinus . It was in 1906 by Maxwell Tylden Masters in the Journal of the Linnean Society Botany , Volume 37, page 416 firstdescribed . Masters pointed to the similarity with the Japanese red pine ( Pinus densiflora ) and the forest pine ( Pinus sylvestris ), whose distribution areas are, however, significantly more northern. The external characteristics of the species lie between those of Pinus yunnanensis , which has a similar distribution area, and the Chinese pine ( Pinus tabuliformis ), whose distribution area is also further north. It could therefore be a hybrid of the two species. This is confirmed by genetic engineering studies, with evidence of the involvement of an unknown third species that disappeared before the Quaternary . Due to the ecological and geographical separation, there is no evidence that new hybrids are being formed. The taxon is usually treated as a separate species.
Synonyms of the species are Pinus prominens Masters , Pinus sinensis D. Don var. Densata ( Masters ) Shaw , Pinus tabuliformis Carriere var. Densata ( Masters ) Rehder and Pinus wilsonii Shaw (1911) not Roezl (1857).
The generic name Pinus was already used by the Romans for several types of pine. The specific epithet densata is possibly derived from the Latin densatio for "thickening" and could thus refer to the clearly developed apophysis.
use
Pinus densata is hardly used economically as it only occurs in the high mountains in rather inaccessible areas. Until the end of the 19th century, torches were still made from the wood and the resin. However, consideration is being given to using the species for afforestation at high altitudes in western China. Pinus densata was introduced to Europe around the turn of the 20th century, but it is rarely found in botanical gardens and arboretums .
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 661, 662 .
- Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . Volume 4: Cycadaceae through Fagaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1999, ISBN 0-915279-70-3 , pp. 16 (English).
- Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 487 (reprint from 1996).
Individual evidence
- ↑ a b c d e f Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 662
- ↑ a b c d Liguo Fu, Nan Li, Thomas S. Elias, Robert R. Mill: Pinus densata , in Flora of China , Volume 4, p. 16
- ^ Tropicos. [1]
- ↑ Pinus densata in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Retrieved on February 10, 2013.
- ↑ Pinus densata. In: Germplasm Resources Information Network (GRIN). United States Department of Agriculture, accessed February 10, 2013 .
- ↑ To be precise: Etymological dictionary of botanical plant names. P. 487
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 661
Web links
- Christopher J. Earle: Pinus densata. In: The Gymnosperm Database. www.conifers.org, November 28, 2012, accessed February 10, 2013 .
- Pinus densata. In: The Plant List. Retrieved February 10, 2013 .