Pinus culminicola
| Pinus culminicola | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Pinus culminicola |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Pinus culminicola | ||||||||||||
| Andresen & Beaman |
Pinus Culminicola is a plant from the genus of pine trees ( Pinus ) within the family of the Pinaceae (Pinaceae). It only thrives in two Mexican states in multiple peak regions. It is classified as "critically endangered" inthe IUCN Red List .
description
_-_cone.jpg)
Appearance
Pinus culminicola grows as an evergreen shrub and reaches heights of 1 to 5 meters. The trunks reach a diameter of 15 to 25 centimeters. The bark is initially gray-brown, soon gray due to the weather, thin, scaly and flakes off in small, irregularly shaped plates. The main branches often grow prostrate to ascending, secondary branches ascending to upright. Young shoots are short, thick, hairless, initially light brown and later gray.
Buds and needles
The scale leaves are initially light brown and turn blackish gray as a result of the weather. They are small, narrowly triangular to sub-like , with a pointed tip and an irregularly serrated leaf margin. The vegetative buds are slightly resinous and broadly ovate. Terminal buds are 6 to 10 millimeters long, lateral ones a little shorter.
The needles usually grow in groups of five, very rarely in groups of four or six, in an initially 6 to 8 millimeter long, straw-colored to gray needle sheath, the scales of which later separate and bend back to form a rosette at the base of the needle bundle. The rosette remains for a long time, but falls off before the needles. The needles are upright to ascending. They are curved, stiff, 3 to 5 inches long and 0.9 to 1.3 millimeters wide. They are entire or have a closely sawn edge. The end of the needle is blunt. The needles are gray-green and adaxially whitish or glaucous . Only the adaxial sides each show four to five stomata lines . Two resin channels are formed. The needles stay on the tree for two to three years.
Cones and seeds
The pollen cones are initially yellowish and later yellowish brown and with a length of 5 to 8 millimeters they are ovate-oblong.
The seed cones grow near the ends of the branches, singly or in pairs, on short, sturdy stalks covered with awl, tailed lower leaves . Fully grown cones are almost round when closed, 3 to 4.5 centimeters long when opened, 3 to 5 centimeters in diameter, and have a flattened base. Usually 20 to 30, rarely up to 40 seed scales are formed. Near the base are barren scales that open only a little, the fertile scales open wide. They are irregularly shaped, often curved, thin, and have one or two deep, cup-shaped indentations that contain the seeds. The apophysis is slightly raised, rhombic to pentagonal in outline, keeled transversely, yellowish brown in color and often resinous. The umbo lies dorsally and is slightly raised, rhombic in outline, reinforced with a small spike or unreinforced.
The brown seeds are 5 to 7 millimeters long and 4 to 5 millimeters in diameter and are obliquely obovate. The integument is 0.8 to 1 millimeter thick. Seed wings are missing when the seeds have detached from the seed scales.
Occurrence and endangerment
The natural range of Pinus culminicola is in Mexico in the states of Coahuila and Nuevo León . It grows at altitudes of 3000 to 3700 meters, which includes the peaks of the mountains. The habitus is similar to that of other small pines in mountain regions, such as the mountain pine ( Pinus mugo ) in Europe or the dwarf pine ( Pinus pumila ) in Asia. The reason for this is the adaptation to snow and sand storms and short growing seasons. The subsoil is mostly rocky and calcareous. Due to the lack of weather stations near the peaks, little is known about the climate, but there is likely to be abundant rainfall, sometimes in the form of snow. 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 ).
At Cerro Potosí , the highest peak of the Sierra Madre Oriental , Pinus culminicola forms extensive pure stands of specimens growing close together. Pinus hartwegii can also be found scattered , which indicates that the tree line has not yet been reached in this region at 3700 meters. At lower altitudes in the Sierra La Marta in Coahuila it grows together with various oak species ( Quercus spec.), Species of the bearberry genus ( Arctostaphylos ), sacred flowers ( Ceanothus ), agaves ( agave ) and various grasses. The flora on Cerro La Viega and in the Sierra de Arteaga in Coahuila is similar, but representatives of the firs ( Abies ) and Douglas firs ( Pseudotsuga ) also thrive here . At Cerro Potosí, the pollen is released late in July, which indicates a short growing season.
In the Red List of the IUCN is Pinus Culminicola classified as "critically endangered" as (= "Endangered"). The species is only known from a few peak regions. The best-known stocks are located on Cerro Potosí and cover several square kilometers, but they have been greatly reduced by fires. Most of the other nine to ten populations are much smaller, the total populations are highly dispersed and specimens are only found on the mountain tops, not in the valleys in between. The greatest threat comes from fires during the long dry spells, and fires have already destroyed part of the population. The stocks are only regenerated slowly. The frequency of fire is likely to increase further due to the increased occurrence of hikers and mountaineers. Another danger comes from climate change, as the species is restricted to a very narrow ecological niche. But at least the stocks at Cerro Potosí are in a protected national park, and the destroyed stocks are slowly being renewed (as of 2012).
Systematics and research history
The first description of Pinus culminicola was in 1961 by John William Andresen and John Homer Beaman in Journal of the Arnold Arboretum , Volume 42, page 438, f. 2-4. The specific epithet culminicola comes from Latin and means something like "grows on the summit" and thus refers to the range of the species.
The species Pinus culminicola belongs to the subsection Cembroides from the Parrya section in the subgenus Strobus within the genus Pinus .
Aljos Farjon distinguishes neither subspecies nor varieties in his book A Handbook of the World's Conifers 2010 . In Conifers of the World 2009, James E. Eckenwalder describes four varieties that Farjon 2010 and Flores-Rentería et al. 2013 to be assigned to other species:
Pinus culminicola var. Remota (E. Little) Eckenwalder : Farjon regards this taxon as a separate species Pinus remota . Pinus culminicola var. Johannis and Pinus culminicola var. Bicolor (E. Little) Eckenwalder were classified as Pinus johannis and Pinus discolor as separate species in 2013 after phenological and genetic studies .
use
Pinus culminicola is not used economically, although the wood may be used locally as firewood. It could become important as an ornamental shrub for rock gardens . Shrubs in the Royal Botanic Garden Edinburgh that were grown from seeds found by Michael P. Frankis in 1991 and later do well. Nevertheless, they are rarely found in culture.
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 978-90-04-17718-5 , pp. 609, 657-658 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 423-425 .
Individual evidence
- ↑ a b James E. Eckenwalder: Conifers of the World , p. 424
- ↑ a b c d e f g h i Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 658
- ↑ a b James E. Eckenwalder: Conifers of the World , p. 425
- ↑ a b Christopher J. Earle: Pinus culminicola. In: The Gymnosperm Database. www.conifers.org, 2019, accessed April 24, 2019 .
- ↑ Pinus culminicola in the endangered Red List species the IUCN 2013. Posted by: Aljos Farjon, 2011. Accessed April 24 of 2019.
- ↑ Pinus culminicola at Tropicos.org. Missouri Botanical Garden, St. Louis, Retrieved April 24, 2019.
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 657
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 609
- ↑ James E. Eckenwalder: Conifers of the World , pp. 424-425
- ↑ Lluvia Flores-Rentería, Ana Wegier, Diego Ortega Del Vecchyo, Alejandra Ortíz-Medrano, Daniel Piñero, Amy V. Whipple, Francisco Molina-Freaner, César A. Domínguez: Genetic, morphological, geographical and ecological approaches reveal phylogenetic relationships in complex groups, an example of recently diverged pinyon pine species (Subsection Cembroides) . In: Molecular Phylogenetics and Evolution . tape 69 , no. 3 . Elsevir, 2013, p. 940-949 , doi : 10.1016 / j.ympev.2013.06.010 .
Web links
- Vascular Plants of the Americas : Pinus culminicola at Tropicos.org. In: 83 . Missouri Botanical Garden, St. Louis