Mexican nut pine
| Mexican nut pine | ||||||||||||
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Pinus cembroides in the Chisos Mountains , Big Bend National Park , Texas |
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| Pinus cembroides | ||||||||||||
| Zucc. |
The Mexican nut pine ( Pinus cembroides ) is a large, evergreen conifer from the genus of the pine ( Pinus ) with needles that usually grow in threes and are 3 to 6 centimeters long. The seed cones usually reach a length of 3 to 5 centimeters. The Mexican nut pine is classified as not endangered in the IUCN Red List , but two of its subspecies are endangered or endangered.
description
Appearance
The Mexican nut pine grows as an evergreen shrub or tree that reaches a height of 15, rarely up to 25 meters. The trunk reaches chest height diameters of 10 to 80, sometimes up to 120 centimeters and often forks. The trunk bark is gray to gray-brown, thick, rough and scaly and breaks up into irregular, small plates separated by shallow furrows. The branches grow spread out and ascending or hanging close to the ground. In young trees they form a dense, oval crown, in older trees an open, wide-spread crown with sparsely needled branches. Young shoots are hairless, sometimes delicately warty, initially orange-brown or slightly blue-green, and soon turn gray.
Buds and needles
The scale leaves are light brown, small, 2 to 4 millimeters long, awl-shaped or triangular, pointed to pointed with an irregularly serrated leaf margin. They fall off early. The vegetative buds are light brown to ocher in color, not or barely resinous and ovate-elongated to oval-cylindrical. Terminal buds are 5 to 8, sometimes up to 10 millimeters long and 3 to 5 millimeters wide, the lateral buds are smaller. The needles usually grow in threes, sometimes in pairs or in groups of four, rarely in groups of five, in a short, 4 to 6 millimeter long needle sheath made of initially pale brown to brown, loosely overlapping scales. These soon bend back, become pale straw-colored to gray and form a small rosette at the base of the needle bundle, which, however, falls off before the needles. The needles are usually curved, more rarely straight, flexible or sometimes stiff, sometimes only 2, usually 3 to 6 and rarely up to 8 centimeters long and rarely from 0.6, usually 0.7 to 1 and sometimes up to 1.2 millimeters wide. They are whole, the end is pointed to pointed or piercing. They are colored differently from matt green to glaucous green, the adaxial sides can also be white. The needles sometimes form droplets of resin. Mostly all sides show stomata lines , only in one variety they are limited to the adaxial sides. On the adaxial sides there are two to three or sometimes four, if there are stomata lines on the abaxial side there are two, three or rarely four. Usually two resin canals are formed , more rarely only one. The needles usually stay on the tree for four to five, sometimes only three or seven years.
Cones and seeds
The pollen cones are yellowish, small, 5 to 10 millimeters long, with a diameter of about 3 millimeters.
The seed cones grow individually, in pairs or rarely in whorls in threes on very short 3 to 5, sometimes up to 8 millimeter long stems that fall off with the cones. Fully grown cones appear sessile and are often resinous. They are irregularly spherical or egg-spherical with closed seed scales, irregularly shaped with open scales with a flattened base and often wider than long. They are 2, usually 3 to 5 and rarely up to 7.5 centimeters long and have a diameter of 3 to 6, rarely up to 7 centimeters. The mostly 20 to 40, rarely up to 50 seed scales open wide and have only a weak connection to the axis, so they can be easily removed. They are 15 to 20 millimeters wide and have one or two deep indentations that contain the seeds. The apophysis is raised, irregularly rhombic to pentagonal in outline, from yellowish green to ocher and reddish brown in color and sometimes shiny. The umbo lies dorsally and is flat or raised, curved and reinforced with a small spike .
The seeds are gray-brown to black-gray or light brown, obliquely obovate, 10 to 16 millimeters long and 6 to 10 millimeters wide. The integument is comparatively thick with 0.5 to 1, rarely 1.1 millimeters, the gametophyte is pink or white. Seed wings are missing.
Chromosome number
The number of chromosomes is 2n = 24.
Distribution, ecology and endangerment
The natural distribution area of the Mexican nut pine is in Mexico and extends from the Sierra Madre Occidental and the Sierra Madre Oriental to the south of central Mexico, there are also stocks in the south of Baja California . In the United States, of course, it only grows near the Mexico border in southeast Arizona , southwest New Mexico, and southwest Texas .
In large parts of the range they are found in the transition zone between desert-like and semi-desert-like valleys and plateaus and the overlying pine-mountain forests with higher rainfall rates. It grows at altitudes from 800, but mostly 1500 to 2600 and rarely up to 2800 meters, whereby it reaches the highest positions in the southeast of the distribution area. The subsoil is very different and varies from alluvial bayadas to volcanic rock. The Mexican nut pine forms open woodland either in the pure stand or together with various types of juniper ( Juniperus spp.), With Pinus nelsonii , Pinus pinceana , various types of oak ( Quercus spp.), Representatives of the palm lily ( Yucca ), the agaves ( agave ), representatives of the Cactus plants (Cactaceae), for example with Opuntia ( Opuntia ), the bearberries ( Arctostaphylos ), the sacred flowers ( Ceanothus ), the strawberry trees ( Arbutus ) and other shrub trees in hot, dry areas. In higher or more humid areas it is part of mixed oak-pine forests, where it grows with, for example, Pinus engelmannii , Pinus leiophylla var. Chihuahuana , and in the southeast of the range with Pinus pseudostrobus . The climate is warm and dry. The annual rainfall ranges from 380 to 650 millimeters with a seven to eight month long dry period. Frost can occur in the higher elevations but is rare. 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 ). For the subspecies Pinus cembroides subsp. lagunae , the distribution area is probably in winter hardiness zone 9 with mean annual minimum temperatures of −6.6 to −1.2 ° Celsius (20 to 30 ° Fahrenheit).
The forests with the Mexican nut pine are home to animals such as the white-tailed deer ( Odocoileus virginianus ), the pronghorn ( Antilocapra americana ), the rock goblet ( Spermophilus variegatus ), the mountain cottontail rabbit ( Sylvilagus nuttallii ) and the piglet kunk ( Conepatus ) leu . The seeds are of Meleagris gallopavo merriami , a subspecies of turkeys , from the thick-billed parrot ( Rhynchopsitta pachyrhyncha ) and by Maron end parakeet ( Rhynchopsitta terresi ) of black bears ( Ursus americanus ), porcupine (Hystricidae), Squirrel (Sciuridae), for example chipmunks ( Tamias ) and other small mammals and birds. From July to September also feed peccaries ( Pecari tajacu ) thereof.
The seeds are wingless and dependent on distribution by birds and rodents. For example, the Florida bush jay ( Aphelocoma coerulescens ) and naked- billed jay ( Gymnorhinus cyanocephalus ) often hide the seeds, which helps spread the jaws when they are no longer found.
The Mexican nut pine is attacked by the rust fungus Cronartium occidentale and by the dwarf mistletoe Arceuthobium divaricatum . If the dwarf mistletoe is infested, growth and seed production decrease, the trees die more frequently and are also more susceptible to disease.
In the Red List of the IUCN is Pinus cembroides classified as endangered ( "Least Concern"). The species is widespread in Mexico and the runners of the range extend to three states in the United States. Even so, two of the subspecies, Pinus cembroides subsp. lagunae and Pinus cembroides subsp. orizabensis , listed as endangered, but they only make up a small part of the total population. In the range of the species there are rarely fires and the trees are rarely felled due to their small size. Some locations are in protected areas.
Systematics and research history
The Mexican nut pine ( Pinus cembroides ) 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 in 1832 by Joseph Gerhard Zuccarini in the Royal Bavarian Academy of Sciences Memoirs of Mathematics and Physics class first described . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet cembroides refers to the similarity of the species with the stone pine ( Pinus cembra ).
The systematics of Pinus cembroides is more controversial than probably that of any other pine species. The species has a wide range and is very variable. In the past, all small-cone pines of the sub-section Cembroides in Mexico and the United States were assigned to this species, later pines with needle bundles usually consisting of one, two, four or five needles were described as separate species. Synonyms of the species are Pinus llaveana Schiede ex Schltdl. and Pinus osteosperma Engelm.
Aljos Farjon distinguishes the following three subspecies and two varieties in A Handbook of the World's Conifers 2010 :
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Pinus cembroides subsp. cembroides with two varieties:
- Pinus cembroides subsp. cembroides var. cembroides
- Pinus cembroides subsp. cembroides var. bicolor Little
- Pinus cembroides subsp. lagunae (Rob.-Pass.) DKBailey
- Pinus cembroides subsp. orizabensis D.K.Bailey
In 1993 Robert Kral distinguishes neither subspecies nor varieties in the Flora of North America and places the trees described by Farjon as a separate species Pinus remota , next to the representatives of the variety bicolor to Pinus cembroides . James E. Eckenwalder sees the representatives of Pinus cembroides subsp. In Conifers of the World in 2009 . lagunae as a separate species Pinus lagunae (Rob. Pass.) Passini and assigns the representatives of the variety bicolor as variety Pinus culminicola var. bicolor (E. Little) Eckenwalder to the species Pinus culminicola .
Subspecies and varieties
Pinus cembroides subsp. cembroides var. cembroides
These are small trees that reach a height of 10 to 15 meters. The needles grow in twos or threes, they are flexible or sometimes stiff, rarely from 2, usually 3 to 5 and sometimes up to 6.5 centimeters long and rarely from 0.6, usually 0.7 to 1.0 millimeters wide. Their color is variable and ranges from matt green to glaucous green , the latter especially on the adaxial sides. The seeds are 10 to 13 millimeters long and 6 to 10 millimeters wide. The integument is 0.6 to 1 millimeter thick, the fresh gametophyte is pink. The natural range of the variety is in the United States in southeast Arizona, southwest New Mexico and southwest Texas; in Mexico in the northeast of Sonora , in Chihuahua , Coahuila , Durango , Zacatecas , Nuevo Léon , in the west of Tamaulipas , in San Luis Potosí and Aguascalientes , in the northeast of Jalisco , in the north of Guanajuato , in Querétaro , Hidalgo , México , Mexico City , Tlaxcala , Veracruz and Puebla .
Pinus cembroides subsp. cembroides var. bicolor
The variety grows shrub-like or as a small tree and reaches heights of 3 to 12 meters. The needles usually grow in threes, rarely in pairs, in groups of four or five. They are more or less stiff, usually 2.5 to 5 and sometimes up to 6 inches long and 0.8 to 1.2 millimeters wide. The color is dull green to gray-green on the abaxial side, and glaucous white on the adaxial side with a green midrib. The seeds are 10 to 12 millimeters long and 6 to 9 millimeters wide. The integument is 0.5 to 1 millimeter thick, the fresh gametophyte is white. The natural range of the variety is in the United States in southeast Arizona and southwest New Mexico; in Mexico in the northeast of Sonora , in Chihuahua , Coahuila , Nuevo Léon , in the west of Tamaulipas , in Durango , Zacatecas and in the north and west of San Luis Potosí . The variety was first described in 1968. In 1978 it became a separate species, Pinus johannis Rob.-Pass. and 1979 as Pinus discolor D.K.Bailey & Hawksw. described, 1985 as a variety Pinus culminicola var. johannis (M.-F. Robert) Silba and Pinus culminicola var. discolor (DKBailey & Hawksw.) Silba also included in the species Pinus culminicola . The type specimen comes from Zacatecas.
Pinus cembroides subsp. lagunae
The trees reach a height of 20 to 25 meters. The needles usually grow in threes, sometimes in twos and very rarely in fours. They are flexible, from 2.5 but usually 4 to 7 and rarely up to 8 centimeters long, from 0.7 usually 0.8 to 0.9 millimeters wide and dull green to gray-green. The seeds are 10 to 16 millimeters long and 6 to 10 millimeters wide. The integument is 0.5 to 0.8 millimeters thick, the fresh gametophyte is pink. The pollen is released in May and June. The natural range is in the Sierra de la Laguna in Baja California Sur , Mexico. The mountain range consists of granite and sedimentary rocks and reaches a height of 2090 meters. The subspecies occurs in the higher northern part at altitudes of 1600 to 2050 meters. It grows best on the La Laguna plateau on sandy-loamy subsoil, but it can also be found in valleys on gravel or granite rock or on slopes with a granite subsoil. It usually grows together with Quercus devia , which is more common in its range than the pine. Except for the subspecies, no other pine grows in Baja California Sur. Tree lily species ( yucca ) and representatives of the genera Calliandra and Dodonaea grow as undergrowth on dry slopes . The climate is subtropical, the annual rainfall is around 750 millimeters, most of which comes down in the summer in thunderstorms.
In the Red List of IUCN the subspecies as endangered ( "Vulnerable") is performed. The distribution area, estimated on the basis of the herbarium finds , extends over about 11 square kilometers, with two to three contiguous stands of altogether more than 1000 trees. The distribution area is protected and there is no current threat of tree felling, also due to the poor accessibility. However, due to the small number of trees, the subspecies is endangered by sporadic events, but also by fires, if their frequency increases, or by the intensification of animal husbandry.
The subspecies was first described in 1981 by Marie-Françoise Robert-Passini as the variety Pinus cembroides var. Lagunae Passini and placed in 1983 by Dana K. Bailey as a subspecies of Pinus cembroides . In 1987 it was classified by her as a separate species Pinus lagunae (Passini) Passini , but this is not recognized, the name is only a synonym.
Pinus cembroides subsp. orizabensis
The trees are small and only reach heights of 8 to 10 meters. The needles usually grow in threes, sometimes in groups of four and rarely in pairs or in groups of five. They are more or less stiff, from 2 but mostly 3 to 5 and rarely up to 8 centimeters long, 0.7 to 1.1 millimeters wide and dull green to gray-green. The seeds are 10 to 14 millimeters long and 6 to 10 millimeters wide. The integument is 0.1 to 1.1 millimeters thick, the fresh gametophyte is pink. The pollen is likely to be released in May and June. The species grows naturally in the Mexican states of Puebla, Tlaxcala and Veracruz at altitudes of 2100 to 2800 meters in a semi-arid climate. It is characterized by a long dry period from November to May and extensive rainfall in summer. The annual rainfall is 800 to 900 millimeters. There can be frost in December and January. There are isolated extinct volcanoes in the distribution area and the subsoil is mostly of volcanic origin. The subspecies forms open woodland and sometimes also dense pure stands, but it usually grows together with the alligator juniper ( Juniperus deppeana ) and Juniperus flaccida . Sometimes it is found together with Pinus pseudostrobus or with different types of oak ( Quercus spp.). However, it is not found together with representatives of the subspecies Pinus cembroides subsp. cembroides .
In the Red List of the IUCN , the subspecies is as endangered ( "Endangered") listed. The distribution area is small and is located in an area in which agricultural areas spread and the forest areas push back. Therefore, there is a steady decline in populations at least in parts of the range. In addition, there are no protective provisions for the area in which the stocks occur.
The subspecies was first described by Dana K. Bailey in 1983 . John Silba assigned her in 1990 as Pinus cembroides var. Orizabensis (DKBailey) Silba only the status of a variety. In 1992 it became a separate species Pinus orizabensis (DKBailey) DKBailey & Hawksw. described. However, the last two classifications are not recognized, the names are synonyms.
use
Pinus cembroides is of great economic importance in Mexico because of its edible seeds. The seeds are regularly harvested and marketed in the fall when the cones open. They contain about 15 percent protein, 62 percent fat and 17 percent carbohydrates. They therefore have a comparatively high protein content. They are eaten raw, roasted, ground in order to bake bread or cakes from the flour, or processed into a cream similar to peanut butter .
Due to its low height and the many branches, the wood is of little importance. It is used for carpentry work, or as firewood in areas where no other pine species are found. Due to its good adaptation to the semi-arid climate and its wide distribution, it is used as an erosion protection or as a shade tree in agriculture. It is rarely planted in gardens and parks, but is used for landscaping in the United States. Otherwise they are mostly only found in arboretums and 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. 650-652 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 420-421, 441 .
- 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
- ↑ German name after Robert Zander : Zander. Concise dictionary of plant names. Edited by Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold . 17th edition. Eugen Ulmer, Stuttgart 2002, ISBN 3-8001-3573-6 , quoted from Pinus cembroides in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
- ^ A b Robert Kral: Pinus cembroides , in Flora of North America. Volume 2
- ↑ a b c d e f g Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 650.
- ↑ a b c d e James E. Eckenwalder: Conifers of the World , p. 420.
- ^ Tropicos
- ↑ a b c d e Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 651.
- ↑ a b James E. Eckenwalder: Conifers of the World , p. 441.
- ↑ a b c d Pinus cembroides. In: Fire Effects Information System. US Forest Service, accessed September 15, 2013 .
- ↑ Pinus cembroides in the endangered Red List species the IUCN 2013. Posted by: Aljos Farjon, 2011. Retrieved on September 1, 2013.
- ↑ a b James E. Eckenwalder: Conifers of the World , p. 421.
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 609.
- ^ Pinus cembroides. In: The International Plant Name Index. Retrieved September 1, 2013 .
- ↑ To be precise: Etymological dictionary of botanical plant names. P. 487.
- ↑ Christopher J. Earle: Pinus cembroides. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed on September 15, 2013 .
- ^ Pinus cembroides. In: The Plant List. Retrieved September 1, 2013 .
- ^ A b Aljos Farjon: A Handbook of the World's Conifers. Volume 2, pp. 651-652.
- ↑ James E. Eckenwalder: Conifers of the World , p. 424.
- ↑ a b c d e f Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 652.
- ↑ a b c Pinus cembroides subsp. lagunae in the endangered Red List species the IUCN 2013. Posted by: Aljos Farjon, 2011. Accessed September 5, 2013.
- ↑ a b c Pinus cembroides subsp. orizabensis in the endangered Red List species the IUCN 2013. Posted by: Aljos Farjon, 2011. Retrieved on September 6, 2013.
- ↑ Pinus cembroides in Plants For A Future . Retrieved September 14, 2013.
Web links
- Pinus cembroides at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed September 1, 2013.
- Pinus cembroides in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.