Alligator Juniper

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Alligator Juniper
Juniperus deppeana StrawberryAZ.jpg

Alligator Juniper ( Juniperus deppeana )

Systematics
Order : Conifers (Coniferales)
Family : Cypress family (Cupressaceae)
Subfamily : Cupressoideae
Genre : Juniper ( Juniperus )
Section : Sabina
Type : Alligator Juniper
Scientific name
Juniperus deppeana
Steud.

The alligator juniper ( Juniperus deppeana ) is a plant from the genus of juniper ( Juniperus ) in the family of cypress plants (Cupressaceae).

description

Branch with needles

Habitus

The alligator juniper is an evergreen tree or shrub that reaches heights of growth of around 10 to 15 (rarely up to 21) meters and a diameter of 25 to 120 centimeters at chest height . The canopy of freestanding trees is wide and unevenly conical. They have a relatively short and strong trunk. The shrub shape grows wide and expansive. The square branches reach a diameter of about 1 millimeter.

bark

bark

The name of the alligator juniper is derived from the dark reddish-brown to blackish colored bark , which is reminiscent of the skin of alligators due to its regular rectangular scaling . It becomes between 2.5 and 10 centimeters thick. The scales reach a diameter of 2.5 to 5 centimeters. Deeper layers of bark are colored reddish brown to purple. The thin twigs have a pale blue-green bark , which turns light reddish brown when the needles fall off.

Wood

The light yellow heartwood , sometimes with red stripes, differs in color from the narrow whitish sapwood . The wood is light, soft, dense-fiber, durable and brittle. The bulk density is / cm³ depending on the specified source with 0.453 or 0.58 g.

leaves

The alligator juniper has needle-like and scale-shaped leaves . The indistinctly keeled scale leaves are 1 to 3 millimeters long and have a bluish-green color. Two or three of you stand on the branch and overlap. They have a blunt or pointed end and a point-shaped gland. The needle-shaped leaves, keeled on the underside, are longer than the scale leaves and suddenly taper to a point. They are mainly found on young trees. There are two or three of you standing on the branch.

Flowers, cones and seeds

Branch with berry cones

Alligator junipers are dioecious gendered ( dioecious ) and wind-flowered ( anemophilia ). The flowering period extends from January to March. The approximately 3 millimeters long male flowers are fleshy and consist of 10 to 12 scale-shaped stamens. The ovules of the female cones are located on the egg-shaped and pointed scales. The initially blue-gray, 8 to 12 millimeters large, berry-shaped cones are only ripe in the 2nd year in September to December and then red-brown and white frosted. The edible “pulp” is dry, floury and aromatic when ripe. Each stalked cone contains 3 to 5 brown seeds about 5 millimeters in size .

The seeds are somewhat flattened on one or two sides. The thousand grain weight is around 35.71 grams.

Chromosome number

This type of juniper has a chromosome number of 2n = 22.

Distribution and location

Distribution map
Alligator Juniper ( Juniperus deppeana ), branch with cones

The natural range of the alligator juniper including its varieties is mainly in the southwest and central south of the USA and in northern Mexico . It stretches from the mountains in central and southern Arizona across southwest New Mexico and west of Texas southwards to the Mexican provinces of Sonora , Chihuahua and Coahuila . Furthermore, this species occurs in isolated areas in central Mexico, also in southern Mexico and in bordering Guatemala .

The alligator juniper colonizes dry limestone soils, mostly at the tree line at altitudes of 1,330 to 2,660 meters. It often occurs together with the stone pine ( Pinus edulis ), the single-leaved pine ( Pinus monophylla ), the yellow pine ( Pinus ponderosa ), various oak species ( Quercus ) and other juniper species ( Juniperus ). It is rarely found in European collections.

Systematics

The alligator juniper ( Juniperus deppeana Steud. ) Is placed within the genus Juniper ( Juniperus ) in the subgenus or the Sabina section, depending on the author . It is divided into different varieties , some of which are referred to in various sources as forms and occasionally also as subspecies . This is followed by Robert P. Adams and Andrea E. Schwarzbach who, after analyzing DNA sequences, describe four varieties in 2006 and give three forms within the variety Juniperus deppeana var. Deppeana . Synonyms for Juniperus deppeana Steud. are Juniperus mexicana Schiede & Deppe and Juniperus pachyphloea Torr. The specific epithet deppeana was chosen in honor of the German naturalist Ferdinand Deppe .

Varieties and forms

A distinction is made between the following varieties :

  • Juniperus deppeana Steud. var. deppeana (Syn .: Juniperus deppeana var. pachyphlaea (Torr.) Martínez ), the nominate form, occurs in the US states of Arizona , New Mexico and Texas ; also in the Mexican states of Sonora , Coahuila , Nuevo León , Tamaulipas , Zacatecas , San Luis Potosí , Aguascalientes , Hidalgo , México , Puebla , Tlaxcala , Veracruz with three forms:
    • Juniperus deppeana Steud. var. deppeana f. elongata R.P.Adams is a dispersed form in the Davis Mountains of Trans-Pecos, Texas.
    • Juniperus deppeana Steud. var. deppeana f. sperryi (Correll) RPAdams is also described in other sources as the variety Juniperus deppeana var. sperryi Correll . This form is known in only three holdings in the Davis Mountains of the Trans-Pecos, Texas region and possibly with a find in the Mexican state of Sonora. The shape has a furrowed bark that comes off in strips.
    • Juniperus deppeana Steud. var. deppeana f. zacatecensis (Martínez) RPAdams is also known as the Juniperus deppeana Steud variety . var. zacatecensis Martínez and is found in the Mexican states of Zacatecas , the neighboring Durango and Aguascalientes . This form is found in forest landscapes and grassy areas on hills along with oaks, pines, pinyons and other junipers. The distribution area is limited to altitudes between 1,980 and 2,470 m.
  • Juniperus deppeana Steud. var. gamboana (Martínez) RPAdams is common in the Mexican state of Chiapas and in the neighboring department of Huehuetenango in Guatemala . In the mountains of Chiapas, this variety colonizes limestone soils in pine, oak and juniper forests at altitudes of 1,670 to 2,200 m. In Guatemala, this juniper is found on limestone slopes in the Sierra de los Cuchumatanes at heights of 1,920 to 2,140 m. Some authors also regard it as a separate species: Juniperus gamboana Martínez .
  • Juniperus deppeana Steud. var. patoniana (Martínez) Zanoni occurs in the north of the state of Sonora and in the state of Durango in Mexico.
  • Juniperus deppeana Steud. var. robusta Martínez occurs in the Mexican states of Sonora, Chihuahua , Durango and Zacatecas . This variety is between 10 and 25 meters high and the bark between 2 and 4 centimeters thick.

use

The wood of the alligator juniper is used as fuel and for the manufacture of fence posts. It can only be made into paper after it has been mixed with wood from other types. The berry cones served as food for various Indian tribes .

Hazards and protective measures

The alligator juniper is listed by the International Union for Conservation of Nature ( IUCN) in the Red List of Endangered Species and is generally designated as “Least Concern”. However, parts of the species, namely one variety and two forms, are listed as endangered. These are the following taxa (IUCN lists all three as varieties):

  • Juniperus deppeana Steud. var. robusta Martínez is still used by the IUCN as a unit with the Juniperus deppeana Steud variety, which has been split off by other sources . var. patoniana ( Martínez ) Zanoni and therefore ranked together with her in the threat level ("Vulnerable"). Intensive deforestation in parts of the distribution area, goats and overgrazing are given as causes of danger. Coppice -use of the trees and protect the large specimens as shade lead to an unbalanced portfolio. The range of the variety is large, but the subpopulations are small and dispersed.
  • Juniperus deppeana Steud. var. deppeana f. sperryi ( Corell ) RP Adams - IUCN lists this form as Juniperus deppeana Steud. var. sperryi Corell as critically endangered, as overgrazing and fire do not give sufficient opportunities to recover the small population (approx. 50 fully grown specimens).
  • Juniperus deppeana Steud. var. deppeana f. zacatecensis ( Martínez ) RP ADAMS - the IUCN also regards this form as a variety Juniperus deppeana Steud. var. zacatecensis Martínez and lists them as endangered ("Endangered"). The population is small and decreasing. The distribution area is in a region where pasture farming is practiced. The main sources of risk are logging and clearing of land for agriculture.

literature

  • Peter Schütt, Horst Weisgerber, Hans J. Schuck, Ulla Lang, Bernd Stimm, Andreas Roloff: Lexicon of Conifers. Distribution - Description - Ecology - Use; the great encyclopedia . Nikol, Hamburg 2004, ISBN 3-933203-80-5 , p. 209-212 .

Web links

Commons : Alligator Juniper ( Juniperus deppeana )  - Album with pictures, videos and audio files

Individual evidence

  1. ↑ Juniperus deppeana in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 4, 2010.
  2. ^ Robert P. Adams, Andrea E. Schwarzbach: Infraspecific adjustments in Juniperus deppeana (Cupressaceae) . In: Phytologia . tape 88 , no. 3 , 2006, p. 227–232 ( PDF ( memento of September 13, 2011 in the Internet Archive )).
  3. ^ Al Schneider: Southwest Colorado Wildflowers, Ferns, & Trees. Archived from the original on April 17, 2010 ; accessed on June 16, 2020 (English).
  4. ↑ Juniperus deppeana var. Sperryi in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  5. ↑ Juniperus deppeana var. Zacatecensis in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 4, 2010.
  6. ↑ Rafaël Govaerts (ed.): Juniperus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved March 28, 2019.
  7. ↑ Juniperus deppeana var. Robusta in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 4, 2010.
  8. ↑ Juniperus deppeana in the endangered Red List species the IUCN 2013. Posted by: A. Farjon, 2011. Accessed July 17, 2020th
  9. ↑ Juniperus deppeana var. Robusta in the endangered Red List species the IUCN 2013. Posted by: A. Farjon, 2011. Retrieved on July 17, 2020.
  10. ↑ Juniperus deppeana . Var sperryi in the endangered Red List species the IUCN 2013. Posted by: A. Farjon, 2011. Retrieved on July 17, 2020.
  11. ↑ Juniperus deppeana . Var zacatecensis in the endangered Red List species the IUCN 2013. Posted by: A. Farjon, 2011. Retrieved on July 17, 2020.