Pinus quadrifolia
| Pinus quadrifolia | ||||||||||||
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Pinus quadrifolia |
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| Pinus quadrifolia | ||||||||||||
| Parl. Ex Sudw. |
Pinus quadrifolia is a small, evergreen conifer from the genus of the pine ( Pinus ) with usually four-growing needles, usually 2 to 4 centimeters long. The seed cones reach a length of 4 to 6 centimeters. The natural range is in southern California and northern Mexico. It is classified as not endangered inthe IUCN Red List .
description
Appearance
Pinus quadrifolia grows as an evergreen , 10 to 15 meter high tree or shrub . The trunk reaches a diameter of 30 to 50 centimeters at chest height . The largest specimen found in the United States was measured in 1976 and had a height of 16.6 meters, a trunk diameter of 70 centimeters and a crown diameter of 12.8 meters. The trunk is short, erect and usually branches just above the ground. The trunk bark is initially smooth and reddish brown and later breaks up into thick, roughly rectangular, gray-brown plates that are separated by flat, vertical and horizontal furrows. The branches are ascending or spread out, higher-order branches are thin. The crown is dense, initially conical and later becomes rounded until it develops into a broad, open crown on older trees. Young shoots are yellowish-brown, hairless or with only very short hairs, strong and rough due to short downward pulvini and small scale leaves. They later bald and turn gray.
Buds and needles
The vegetative buds are egg-shaped-conical, pointed, orange-brown and slightly resinous and usually 4 to 8, rarely up to 14 millimeters long with a diameter of 4 to 5 millimeters. The needles usually grow in groups of four, more rarely in groups of three or five, in needle sheaths that are initially 5 to 8 millimeters long. Sometimes you will find a few bundles of needles with one, two or six needles. The needle sheath breaks up in scales that bend back and which soon fall off, but sometimes can form a rosette beforehand. The needles are curved, more rarely straight, stiff, sometimes from 1.5, usually 2 to 4 and rarely up to 5 centimeters long and from 0.8 usually 1.0 to 1.5 and rarely up to 1.7 millimeters thick, with entire margins and pointed -stinging. They are gray-green to bluish green and show two whitish stomata lines on the adaxial sides. Usually two, more rarely only one or three large resin canals are formed. The needles sometimes only stay on the tree for three, usually four to seven years.
Cones and seeds
The pollen cones are initially purple-red and later turn yellow. They are ovate-round to short cylindrical and 7 to 10 millimeters long.
The seed cones grow individually or in whorls of two to four on short, thin stalks that fall off with the cone. Fully grown cones are closed ovoid-rounded to rounded, open irregularly shaped, 4 to 6 centimeters long with a diameter of 4.5 to 7 centimeters. The 25 to 35 and rarely up to 50 seed scales open wide, are easily mobile, irregularly shaped and have one or two depressions which contain the seeds. The apophysis is ocher-colored, yellowish brown to reddish brown, often resinous, thick woody, raised, bluntly conical to pyramidal, keeled across, straight or curved back. The umbo is dorsal. It is flat or truncated pyramidal. The cones ripen after two years, give off the seeds and then soon fall from the tree.
The seeds are brown, obliquely obovate or elliptical, 12 to 18 millimeters long and 8 to 12 millimeters wide. The integument is comparatively thin at 0.3 to 0.5 millimeters. The seeds initially have a rudimentary wing that remains on the seed scale when the developed seed is released.
Distribution and ecology
The natural range of Pinus quadrifolia is in the Peninsular Ranges in Riverside County and San Diego County in California and extends to the Sierra de San Pedro Mártir in Mexico in the state of Baja California Norte . The species grows at altitudes of 900 to 2400 meters, more rarely up to 2700 meters between Chaparral and the mixed forests of the summit region. The subsoil consists mostly of granite, in the southern part of the distribution area also of volcanic rock. It often grows out of rock crevices. The annual rainfall is 300 to 500 millimeters, which falls in thunderstorms in winter. Spring and summer form a long dry period. The distribution area is assigned to winter hardiness zone 7 with mean annual minimum temperatures of −17.7 to −12.3 ° Celsius (0 to 10 ° Fahrenheit ).
Pinus quadrifolia sometimes forms pure stands and is more common than the single-leaved pine ( Pinus monophylla ), but in California it often grows together with this species. In Mexico it is only found together with the Jeffrey pine ( Pinus jeffreyi ). Otherwise it often grows together with the Californian juniper ( Juniperus californica ) and the oak species Quercus tubinella , in the chaparral with different shrubs such as representatives of the genera Adenostema , the sacred flowers ( Ceanothus ), Artemisia , Cercocarpus , Rhus , Eriodyictyon , the bearberry ( Arctostaphus ) and the palm lilies ( yucca ).
Hazard and protection
In the Red List of the IUCN is Pinus quadrifolia classified as endangered ( "Least Concern"). The extent of occurrence is small, but large enough that no hazard can be derived from it. There are 51 known stocks that cover an area of only about 1150 square kilometers ("area of occupancy"), which falls below the limit for endangered species. However, there is no evidence of a decline in stocks. The trees are not felled for wood use and the species is well adapted to the regularly occurring fires. Parts of the range are protected in both the United States and Mexico.
Systematics and research history
Pinus quadrifolia is a species from the genus of the pines ( Pinus ), in which it is assigned to the subgenus Strobus , section Parrya , subsection Cembroides . The species was first validly described in 1897 by George Bishop Sudworth in the Bulletin of the Forestry Division of the United States Department of Agriculture , using a name from Filippo Parlatore . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet quadrifolia comes from Latin and means four-leaved. It refers to the usual number of needles per needle bundle. Synonyms include Pinus juarezensis Lanner , Pinus parryana Engelm. , Pinus cembroides var. Parryana Voss and Pinus cembroides var. Quadrifolia (Parl. Ex Sudw.) Silba .
Pinus quadrifolia is a very variable species in terms of the number of needles per needle bundle that can occur in a stand. The most common are four needles, which also earned it the scientific name, but there are trees that show almost only five-needle bundles, three-needle bundles are common and double-needle and single-needle ones also occur. This led to the assumption that it is not a species, but a hybrid between an almost extinct five-needle species and Pinus monophylla , with whose range there is overlap. Crossings of the two species result in trees that usually form bundles of two or three needles, which supports this view. On the other hand, genetic studies show that there are closer relatives of Pinus quadrifolia than Pinus monophylla .
use
The wood is not used economically, but is used locally as firewood. The seeds are edible, harvested regularly and also traded in local markets. The resin is also used to a lesser extent. The species is rarely planted as an ornamental tree, but it is sometimes found in botanical gardens.
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literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 978-90-04-17718-5 , pp. 609, 747-748 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 469-470 .
- 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 c d e f g h Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 747
- ↑ James E. Eckenwalder: Conifers of the World , p. 470
- ↑ a b c d e f g James E. Eckenwalder: Conifers of the World , p. 469
- ^ A b c Robert Kral: Pinus quadrifolia , in Flora of North America. Volume 2
- ↑ a b c Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 748
- ↑ Pinus quadrifolia in the endangered Red List species the IUCN 2013. Posted by: A. Farjon, 2011. Accessed on November 3, 2013.
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 609
- ↑ Pinus quadrifolia. In: The International Plant Name Index. Retrieved November 3, 2013 .
- ↑ To be precise: Etymological dictionary of botanical plant names. P. 487
- ↑ Pinus quadrifolia. In: The Plant List. Retrieved November 3, 2013 .
- ↑ James E. Eckenwalder: Conifers of the World , pp. 469-470
Web links
- Christopher J. Earle: Pinus quadrifolia. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed on November 3, 2013 .
- Pinus quadrifolia at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed November 3, 2013.
- Pinus quadrifolia in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.