Pinus lumholtzii
| Pinus lumholtzii | ||||||||||||
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Pinus lumholtzii |
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| Pinus lumholtzii | ||||||||||||
| BLRob. & Fernald |
Pinus lumholtzii is an evergreen conifer from the genus of pine ( Pinus ) with mostly 20 to 30 centimeters long, hanging needles that grow in groups of three and 3.5 to 5.5 centimeters long seed cones. The natural range is in the Sierra Madre Occidental in Mexico. The species is not endangered. It is hardly used economically and is rarely used in horticulture.
description
Appearance
Pinus lumholtzii grows as an evergreen tree up to 20 meters high. The trunk is straight and reaches a diameter of 50 to 70 centimeters at chest height . The trunk bark is thick, very rough and scaly, dark brown to gray-brown and divided into irregular, elongated plates and deep, wide, vertical cracks. The branches are horizontal or ascending, branches of a higher order, i.e. not the main branches, are thin, flexible and overhanging. The treetop is wide, dome-shaped and mostly open. Young shoots are hairless, initially covered with a layer of wax and later turn reddish brown and then gray.
Buds and needles
The vegetative buds are ovate-conical, pointed and resinous. Terminal buds are about 15 millimeters long with a diameter of 8 millimeters, lateral buds are smaller. The lower leaves, which are designed as bud scales, are red-brown, dry-skinned, awl-shaped and up to 10 millimeters long. The needles grow in threes, only in exceptional cases in twos or fours, in a needle sheath that is initially 20 to 35 millimeters long. The needle sheath consists of about ten reddish-brown scales that soon separate and form a tuft at the base and later fall off completely. The needles are very pendulous, soft, thick, light green, 20 to 30 centimeters, rarely from 15 to 40 and more centimeters long and 1.2 to 1.5 millimeters, rarely only 1.0 millimeters thick. You stay on the tree for two years. The edge of the needle is finely sawn, the end pointed. There are clearly visible stomata lines on all needle sides . Four to eight, rarely up to ten resin canals are formed.
Cones and seeds
The pollen cones grow in small groups. They are initially pink, later yellow, cylindrical and fully grown 2 to 3 centimeters long with a diameter of about 5 millimeters. The seed cones grow on the sides or near the ends of branches, usually singly, more rarely in whorls in twos or threes on 10 to 15 millimeter long, curved stems that break off easily and then remain on the cones. Ripened cones are closed ovoid to ovoid narrowed, open ovoid to ovoid-pointed, from 3 mostly 3.5 to 5.5 and rarely up to 7 centimeters long and from 2.5 mostly 3 to 4.5 centimeters wide. The mostly 60 to 80, rarely from 50 and up to 100 seed scales are thick woody, more or less rectangular, open wide, with the scales close to the base remaining closed or even overgrown. The apophysis is thickened along the outer edge, indistinctly keeled transversely, with a rhombic or pentagonal outline, ocher-colored or reddish brown. The apophysis of the basal scales is bumpy. The umbo is flat or slightly protruding and reinforced with a small, soon sloping sting . The seeds are obliquely obovate, slightly flattened, 3 to 5 millimeters long, dark brown and black-spotted. The seed wings are usually 10 to 14 millimeters long from 8, 4 to 6 millimeters wide, yellowish or gray-brown.
Distribution, ecology and endangerment
The natural range of Pinus lumholtzii is in Mexico in the Sierra Madre Occidental in the states of Chihuahua , Sinaloa , Durango , Nayarit , Jalisco , Zacatecas , Aguascalientes and Guanajuato .
The species grows at altitudes of 1700 to 2600 meters, rarely from 1500 to 2900 meters on the lower and medium-high slopes of the Sierra Madre. 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 ). Annual rainfall is around 500 to 600 millimeters, except in the wettest and driest areas, and falls mostly as summer rain. It usually grows in mixed forests of pine and oak . Other pine trees that are common with Pinus lumholtzii are Pinus leiophylla , Pinus arizonica , Pinus douglasiana , Pinus teocote, and Pinus oocarpa . In areas with higher rainfall they are found together with Pinus ayacahuite and Pseudotsuga menziesii , in drier areas Pinus cembroides can occur together.
In the Red List of the IUCN is Pinus Lumholtzii classified as endangered ( "Lower Risk / least concern"). However, it should be noted that a reassessment is necessary.
Systematics and research history
Pinus lumholtzii is a species from the genus of pines ( Pinus ), in which it is assigned to the subgenus Pinus , Section Trifoliae and Subsection Australes . It was first scientifically described in 1895 by Benjamin Lincoln Robinson and Merritt Lyndon Fernald in the Proceedings of the American Academy of Arts and Sciences . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet lumholtzii honors the Norwegian naturalist Carl Lumholtz (1851–1922), who led the scientific expedition on which the type specimen was found.
Pinus lumholtzii resembles the much larger Pinus patula with its drooping needles , which occurs in the more humid areas of eastern and southern Mexico. More precise analyzes, for example of the falling leaf sheaths, however, suggest a closer relationship with Pinus leiophylla .
use
Due to its scattered occurrence in mixed forests, the species is of little economic importance. However, in some areas it was heavily overused along with other pines because of the wood. The species is known in Mexico as “pino triste” (translated as “weeping pine”) because of its hanging needles, but is still rarely used in horticulture.
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literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 704-705 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 445-446 .
- 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
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 704
- ↑ a b c d James E. Eckenwalder: Conifers of the World , p. 445
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, pp. 704-705
- ↑ a b c d Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 705
- ↑ Pinus lumholtzii in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed May 18, 2013.
- ↑ Pinus lumholtzii. In: The Plant List. Retrieved May 18, 2013 .
- ↑ Exactly: Etymological dictionary of botanical plant names p. 487
- ↑ James E. Eckenwalder: Conifers of the World , p. 446
Web links
- Christopher J. Earle: Pinus lumholtzii. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed May 18, 2013 (English).
- Pinus oocarpa at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed May 18, 2013.