Pinus praetermissa
| Pinus praetermissa | ||||||||||||
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| Scientific name | ||||||||||||
| Pinus praetermissa | ||||||||||||
| Styles & McVaugh |
Pinus praetermissa is a plant from the genus of pine trees ( Pinus ) within the family of the Pinaceae (Pinaceae). The natural range is in Mexico. No particular usage is known.
description
Appearance
Pinus praetermissa grows as an evergreen tree or shrub and usually reaches heights of 10 to 15 meters, rarely up to 20 meters. The trunk is twisted or crooked and can branch out near the ground. The chest height diameter is about 30 centimeters. The trunk bark is thin and divided into irregular, elongated and reddish-brown plates, which are separated by shallow furrows. The branches are horizontal, they are long, twisted and form a wide, irregular, open crown. Young shoots are thin, hairless, initially reddish brown and later gray-brown.
Buds and needles
The vegetative buds are not resinous and ovate, oblong to cylindrical. Terminal buds are 10 to 15 millimeters long, lateral buds are oval-pointed and smaller. The low leaves, which are formed as bud scales, are light brown, sub-like , not bent back, 7 to 10 millimeters long and dry-skinned. The needles usually grow in groups of five, less often in groups of four, in an 11 to 14 millimeter long, shortened to 7 to 12 millimeter, permanent, dark brown to gray needle sheath that falls off with the needle bundle. The needles are light green, straight, thin, flexible but not pendulous, from 8 usually 10 to 16 centimeters long and 0.5 to 0.8 millimeters thick. The edge of the needle is finely sawn, the end pointed. There are indistinct stomata lines on all sides of the needle . Usually one or two, rarely up to four, thin resin channels are formed. The needles stay on the tree for two to three years.
Cones and seeds
The pollen cones are pink to reddish and with a length of 1 to 1.5 centimeters and a diameter of about 5 millimeters ovoid-oblong to cylindrical. The seed cones usually grow individually, rarely opposite, near the branch ends on thin, up to 35 millimeters long, curved stems. Fully grown cones are usually 5 to 6.5 (4 to 7) centimeters in length and 5 to 8 centimeters in diameter, usually from 6 to 8 centimeters wide, ovoid to almost round and sometimes wider than long, often open with a flattened base. The mostly 50 to 80 and rarely up to 120 seed scales are elongated, straight or curved back, more or less symmetrical, thinly woody and stiff. The apophysis is flat to slightly elevated, radially striped to transversely keeled, rhombic to pentagonal in outline and shiny light brown to shiny yellowish brown. The umbo lies dorsally, it is flat to slightly raised and blunt.
The black-gray or black-spotted seeds are oblique-ovoid with a length of 5 to 8 millimeters and a diameter of 3 to 4 millimeters. The seed wings are 12 to 18 millimeters long and 5 to 8 millimeters wide.
Occurrence and endangerment
The natural range of Pinus praetermissa lies in Mexico in the states Durango , Jalisco , Nayarit and Sinaloa . In Mexico this species has the most restricted distribution area of all pine species from the subgenus Pinus , only Pinus maximartinezii and Pinus rzedowskii from the subgenus Strobus have smaller distribution areas.
Pinus praetermissa grows in dry, open mixed forests of pines and oaks or in tropical deciduous forests on rocky subsoil at heights of 900 to 1900 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 1000 to 1500 millimeters, from November to May is a dry period. The species grows together with Pinus devoniana , Pinus lumholtzii , Pinus pseudostrobus and possibly with Pinus oocarpa .
In the Red List of the IUCN is Pinus praetermissa "not at risk" (= "Lower Risk / least concern") classified. However, it should be noted that a reassessment is necessary.
Systematics
Representatives of the taxon were assigned to the species Pinus oocarpa until 1990 and only in 1990 by Brian Thomas Styles and Rogers McVaugh in "A Mexican pine promoted to specific status: Pinus praetermissa." in: Contributions from the University of Michigan Herbarium , Volume 17, page 310, f. 1–2 first described as a separate species Pinus praetermissa . The specific epithet praetermissa comes from Latin and means “overlooked” or “ignored” and refers to the fact that the species was not recognized as such for a long time. A synonym for Pinus praetermissa is Pinus oocarpa var. Microphylla Shaw .
The species Pinus praetermissa belongs to the Australes subsection from the Trifoliae section in the Pinus sub-genus within the Pinus genus . Pinus praetermissa is closely related to Pinus oocarpa , although the closed cones in particular are similar. Opened cones of Pinus oocarpa remain on the tree long after the seeds have been released, while the cones of Pinus praetermissa fall off soon after opening. The needles of Pinus praetermissa are shorter and softer and show fewer stomata opening lines and fewer resin canals.
use
There is no known specific use, the wood is probably used in conjunction with other pine species. A horticultural use is not known.
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 740-741 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 466-467 .
Individual evidence
- ↑ a b c d e f g Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 741.
- ↑ a b c d e f g h James E. Eckenwalder: Conifers of the World , pp. 466–467.
- ↑ Pinus praetermissa in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed May 25, 2013.
- ^ Brian Thomas Styles, Rogers McVaugh: Contributions from the University of Michigan Herbarium , Volume 17, p. 310, f. 1-2, 1990 "A Mexican pine promoted to specific status: Pinus praetermissa." scanned at biodiversitylibrary.org with illustration.
- ↑ Pinus praetermissa at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed May 26, 2013.
- ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , pp. 487, 504 (reprint from 1996).
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 740.
Web links
- Vascular Plants of the Americas: Pinus praetermissa at Tropicos.org. In: 83 . Missouri Botanical Garden, St. Louis
- Christopher J. Earle: Pinus praetermissa. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed May 25, 2013 (English).