Pinus herrerae
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Pinus herrerae |
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| Martínez |
Pinus herrerae is an evergreen conifer from the genus of the pines ( Pinus ) with usually 15 to 20 centimeters long needles growing in groups of three and 3 to 3.5 centimeters long seed cones. The natural range is in Mexico. The species is not endangered. The wood and the resin are used economically, but the species is not used in gardens.
description
Appearance
Pinus herrerae grows as an evergreen tree , 30 to 35 meters high. The trunk is straight or sometimes twisted and reaches a diameter of 80 to 100 centimeters at chest height . The trunk bark is thick, rough, reddish brown to gray-brown and divided into scale-shaped plates by flat, longitudinal furrows. The crown is open and almost spherical. The branches are long, thinly overhanging or standing horizontally. The needles are slightly hanging. Young shoots are orange-brown, smooth, hairless and show well-developed pulvini that run down the branch .
Buds and needles
The vegetative buds are ovate-pointed to ovoid-elongated or cylindrical and not resinous. Terminal buds are 10 to 15 millimeters long, lateral buds are smaller. The low leaves, which are formed as bud scales, are brown, awl-shaped and dry-skinned. They have a bent back tip. The needles grow in threes in a needle sheath that is initially up to 20 millimeters long and then shortens to 8 to 15 millimeters, which can be elongated as the needles grow. The needles are yellowish green to light green, thin and flexible, drooping or spreading, 15 to 20, rarely from 10 centimeters long and 0.7 to 0.9 millimeters thick. You stay on the tree for three years. The edge of the needle is finely sawn, the end pointed. There are narrow stomata lines on all needle sides . Usually two or three, rarely only one or four resin channels are formed.
Cones and seeds
The pollen cones are yellowish green and red covered, ovate-oblong to cylindrical and 1.5 to 1.8 centimeters long with a diameter of about 5 millimeters. The seed cones grow near the ends of twigs, individually or in pairs opposite each other, rarely in whorls in threes on 10 to 15 millimeter long, initially straight and later curved stems, which stay on the cones even when they fall off. Ripened cones are closed, narrowly ovoid, open almost symmetrical or slightly curved, ovoid, 3 to 3.5, rarely from 2 to 4 centimeters long with a diameter of two to 3.5 centimeters. The 35 to 85 seed scales are thick, woody, elongated, straight or curved back. The apophysis is slightly raised and keeled transversely, with a wavy or entire end, radially striped and light brown. The umbo is pyramid-shaped and reinforced with a small, sloping spike . The seeds are ovate or obovate, slightly flattened, 2.5 to 4 millimeters long, 2 to 3 millimeters wide and dark gray-brown. The seed wing is obliquely ovate, 5 to 8 millimeters long, 3 to 5 millimeters wide, translucent and yellowish with a dark tone.
Distribution, ecology and endangerment
The natural range of Pinus herrerae is in Mexico in the southwest of the state Chihuahua , in Sinaloa , Durango , Guerrero , Michoacán and in the west and south of Jalisco . It stretches along the Sierra Madre Occidental and along the Sierra Madre del Sur where there are denser stands.
The species grows at altitudes of 1500 to 2600 meters, in the Sierra de Cuale in the west of Jalisco it is found from an altitude of 1100 meters. 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 ). The annual rainfall ranges from 900 to 1600 millimeters and increases towards the south. The dry season lasts from November to May. The forests are mostly pine forests or mixed forests of pine and oak , in which one finds the species together with a large number of other pine species and locally also with representatives of the Douglas firs ( Pseudotsuga ). Other deciduous trees include strawberry trees ( Arbutus ), alders , cinnamon trees ( Clethra ), walnuts ( Juglans ), Persea , Clusia , and linden trees ( Tilia ). In large areas, the forests are heavily influenced by humans, for example by felling large pine trees, by recurring fires or by grazing livestock.
In the Red List of the IUCN is Pinus herrerae as not at risk ( "Lower Risk / least concern") classified. However, it should be noted that a reassessment is necessary.
Systematics and research history
Pinus herrerae 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 not scientifically described for the first time until 1940 by Maximino Martínez in the Anales del Instituto de Biológia de la Universidad Nacional de México . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet herrerae honors the Mexican biologist Alfonso Herrera , a colleague of Maximino Martínez at the University of Mexico.
Pinus herrerae is closely related to the also small-cone Pinus teocote and Pinus lawsonii . Sometimes it is even considered a variety ( Pinus teocote var. Herrerae (Martínez) Silba ) of Pinus teocote .
use
The wood from Pinus herrerae is of good quality and is used throughout the entire area, the resin is extracted economically. It is not known to be used as an ornamental tree .
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 686-687 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 437 .
- 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. 686
- ↑ a b c d e f James E. Eckenwalder: Conifers of the World , p. 437
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, pp. 686-687
- ↑ a b c Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 687
- ↑ Pinus herrerae in the Red List of Threatened Species of the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed May 17, 2013.
- ↑ a b Pinus herrerae. In: The Plant List. Retrieved May 17, 2013 .
- ↑ Exactly: Etymological dictionary of botanical plant names p. 487
Web links
- Christopher J. Earle: Pinus herrerae. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed May 17, 2013 (English).
- Pinus herrerae at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed May 17, 2013.