Pinus leiophylla
| Pinus leiophylla | ||||||||||||
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Pinus leiophylla in Tulancingo , Hidalgo , Mexico |
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| Scientific name | ||||||||||||
| Pinus leiophylla | ||||||||||||
| Different ex Schltdl. & Cham. |
Pinus leiophylla is an evergreen conifer from the genus of pine ( Pinus ) with usually 6 to 15 centimeters long needles and 5 to 7 centimeters long seed cones. The natural range is in Mexico and the southwestern United States. Adistinction is made betweentwo varieties . The species is classified as not endangered inthe IUCN Red List . It was heavily used in the second half of the 20th century because of the wood and the resin is also processed.
description
Appearance
Pinus leiophylla grows as an evergreen tree , usually 15 to 30 meters, rarely up to 35 meters high. The trunk stands upright and reaches a chest height diameter of 20 to 85 centimeters. The trunk bark is very thick, rough and scaly and breaks into dark gray-brown to almost black, elongated, irregular plates that are separated by deep, mainly longitudinal cracks. The long, thin branches are usually horizontal or ascending, lower-lying branches are bent downwards. They form an open, round crown. Young shoots are more or less scaly, initially reddish brown and often covered with a thin layer of wax. They later turn gray-brown.
Buds and needles
The vegetative buds are not or only slightly resinous, ovate-conical and blunt. Terminal buds are 10 to 15 millimeters long with a diameter of 5 to 7 millimeters, lateral buds are smaller. The bracts, which are formed as bud scales, are light orange-brown, lanceolate-subulate , about 6 millimeters long, initially straight and soon bent back. The needles usually grow in groups of three to five, rarely in pairs or up to six in bundles, which are initially surrounded by a 12 to 20 millimeter long, basal needle sheath that falls off early. The needles are yellowish green to bluish green and covered by a thin layer of wax and grow in stiff or flexible, sometimes slightly pendulous clusters at the ends of branches. They are usually 6 to 15 centimeters long, rarely from 4 to 17 centimeters, and 0.5 to 1.3, rarely 1.5 millimeters thick. The edge of the needle is very finely sawn, the end pointed to pointy-piercing. There are narrow but clear stomata opening strips on all sides of the needle . Usually three to six, rarely fewer, resin canals are formed. The needles stay on the tree for two to three years.
Cones and seeds
The pollen cones are yellowish pink, cylindrical, 1 to 1.5, rarely up to 2 centimeters long with a diameter of 4 to 6 millimeters. The seed cones grow individually or in whorls of two to five on strong, 10 to 20 millimeters long, straight or recurved stems near the ends of the branches. Fully grown cones are closed, narrowly ovoid to ovoid and open almost symmetrical, ovoid to broad ovoid, usually 5 to 7 centimeters, rarely from 4 to 8 centimeters long, with diameters from 3 to 4 to 5.5 centimeters. The cones only mature after three years and remain on the tree for several years after the seeds have been released. The 50 to 100, rarely 150, seed scales are straight or bent back at the base of the cones, elongated with almost straight edges. The apophysis is raised and keeled transversely, rhombic in outline, matt brown to gray-brown. The umbo lies in the center of the apophysis and is surrounded by a clearly delimited, narrow band. It is darker than the apophysis, pyramidal and armed with a blunt thorn . The seeds are obliquely egg-shaped, somewhat flattened, 3 to 4 rarely 5 millimeters long, dark gray-brown and spotted with black. The seed wings are 10 to 18 millimeters long, yellowish brown, translucent and have a dark tint.
Branch with needles
Distribution, ecology and endangerment
The natural range of Pinus leiophylla is in Mexico and the southwestern United States. In Mexico you can find them in the west and south of Chihuahua , in Durango , in the east of Sonora , in Zacatecas , Hidalgo , Jalisco , Mexico City , in the state of Mexico , in Michoacan , Morelos , in the east of Nayarit , in Oaxaca , Puebla , Tlaxcala and Veracruz . In the United States, it grows in southwest New Mexico and southeast Arizona .
The variety leiophylla is a widespread tree of the montane and high-montane pine and oak-pine forests on deep, well-drained soils, mostly on volcanic or metamorphic rock. It grows at altitudes from 1900 to 2900 meters, rarely from 1500 to 3300 meters, with the height reached increasing towards the south. The annual amount of precipitation varies greatly depending on the location and altitude and ranges from 700 to 1950 millimeters. In the north of the range and at high altitudes, frost occurs in winter. The distribution area is assigned to winter hardiness zone 9 with mean annual minimum temperatures between −6.6 ° and −1.2 ° Celsius (20 to 30 ° Fahrenheit ). They are usually found together with various oak species and the pines Pinus patula , Pinus pringlei , Pinus teocote , Pinus lawsonii , Pinus pseudostrobus , Pinus montezumae , Pinus douglasiana , Pinus durangensis , at lower altitudes with Pinus oocarpa . In the northwest of the distribution area one finds Pinus arizonica , Pinus engelmannii and the variety Pinus leiophylla var. Chihuahuana . It grows locally with various types of juniper or the Mexican cypress ( Cupressus lusitanica ).
The chihuahuana variety grows roughly in the same area as the leiophylla variety , but only at altitudes of 1500 to 2700 meters, rarely up to 2950 meters, which is also due to the fact that it is absent on some of the high volcanoes in central Mexico. In the Sierra Madre Occidental it occurs at lower altitudes than the variety leiophylla , here it is found in more or less dry habitats together with various types of juniper, with Pinus cembroides and xerophytes such as various types of opuntia ( Opuntia ) and bearberry ( Arctostaphylos ). At higher altitudes the habitat resembles that of the variety leiophylla .
In the Red List of the IUCN is Pinus Leiophylla classified as endangered ( "Lower Risk / least concern"). However, it should be noted that a reassessment is necessary.
Systematics
Pinus leiophylla is a species from the genus of the pines ( Pinus ), in which it is assigned to the subgenus Pinus , Section Trifoliae and Subsection Australes . It was described scientifically valid for the first time in 1831 by Diederich Franz Leonhard von Schlechtendal and Adelbert von Chamisso in Linnaea , based on a description by Christian Julius Wilhelm Schiede . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet leiophylla is made up of the Latin lenis for "soft" and the Greek phyllos for leaf. Synonyms of the species are Pinus comonfortii Roezl , Pinus decandolleana Roezl , Pinus dependens Roezl , Pinus gracilis Roezl , Pinus huisquilucaensis Roezl , Pinus lerdoi Roezl , Pinus lumholtzii var. Microphylla Carvajal , Pinus monte-allegezi Roezl and Pinus monte-allegezi Roezl .
There are two varieties:
- Pinus leiophylla var. Leiophylla : The trees reach heights of 20 to 30, rarely up to 35 meters and trunk diameters of 50 to 85 centimeters. Young shoots are reddish brown and sometimes covered with a thin layer of wax. The needles usually grow in groups of five, less often in groups of four or even less often in groups of six. They are usually 8 to 15 centimeters long, less often from 6 to 17 centimeters, and 0.5 to 0.9 millimeters thick. On the convex abaxial side of the needles there are rarely three, usually four to six and rarely seven stomata, on the two adaxial sides rarely two, usually three or four. Usually two or three, rarely one or four resin channels are formed per needle. The natural range of the variety is in Mexico, in the United States it does not occur.
- Pinus leiophylla var. Chihuahuana ( Engelman. ) Shaw : The trees reach heights of 15 to 25 meters, but mostly not more than 10 meters and trunk diameters of 20 to 60 centimeters. Young shoots are reddish brown and often covered with a thin layer of wax. The needles usually grow in threes, less often in twos or fours, or even less often in groups of five. They are usually 6 to 12 centimeters long, less often from 4 to 14 centimeters, and 0.9 to 1.3, less often up to 1.5 millimeters thick. On the convex abaxial side of the needles there are usually five to eight, more rarely four or nine stomata, and three or four on the two adaxial sides. Usually four to six, rarely three or seven resin channels are formed per needle. The natural range of the variety is in Mexico and the United States. The variety was first described by George Engelmann under the name Pinus chihuahuana as a species of its own, but by Albert Edward Murray as a subspecies Pinus leiophylla subsp. chihuahuana (Engelm.) AEMurray posed to Pinus leiophylla .
use
Like many other pine species, Pinus leiophylla was heavily used in the Sierra Madre Occidental in the second half of the 20th century because of its wood. However, due to the high resin content, the wood is of poor quality. The resin is obtained from resins and further processed. The wood is used as construction timber and to make boxes. The wood of the chihuahua variety is used less, but the resin is also extracted. The species is also planted in plantations outside of its natural range, particularly common in Africa.
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 700-702 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 443-444 .
- Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 2: Pteridophytes and Gymnosperms . Oxford University Press, New York / Oxford a. a. 1993, ISBN 0-19-508242-7 (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 Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 700
- ↑ a b c d James E. Eckenwalder: Conifers of the World , p. 473
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, pp. 700-701
- ↑ a b c d e f Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 701
- ↑ Pinus leiophylla in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved May 20, 2013.
- ↑ Pinus leiophylla in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed May 25, 2013.
- ↑ a b Pinus leiophylla. In: The Plant List. Retrieved May 25, 2013 .
- ↑ Exactly: Etymological dictionary of botanical plant names p. 487
- ^ A b Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 702
Web links
- Christopher J. Earle: Pinus leiophylla. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed May 25, 2013 (English).
- Robert Kral: Pinus leiophylla in Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 2: Pteridophytes and Gymnosperms . Oxford University Press, New York / Oxford a. a. 1993, ISBN 0-19-508242-7 (English).
- Pinus leiophylla at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed May 25, 2013.