Pinus culminicola
Bushes in the Royal Botanic Garden Edinburgh
Pinus culminicola is an evergreen shrub-like growing conifer of the genus pine (Pinus ), usually with five of growing 3-5 inches long needles. The seed cones reach a length of 3 to 4.5 centimeters. The natural range is in Mexico, where it grows in two states in several summits. It is classified as endangered in the IUCN Red List.
- 5.1 Literature
- 5.2 Notes and references
Description
Appearance
Pinus culminicola grows as evergreen, 1-5 m tall shrub. The stems reach 15 to 25 centimeters in diameter. The bark is gray-brown at first, soon by weathering influence gray, thin, scaly and flaking off in small, irregularly shaped plates. The main branches often grow prostrate to ascending, secondary branches ascending to erect. Young shoots are short, thick, glabrous, light brown at first and later gray.
Buds and needles
The scale leaves are initially pale brown and blackish gray stain through the influence of the weather. They are small, narrowly triangular to subulate, with tailed tip and irregularly serrated leaf edge. The vegetative buds are slightly resinous and broadly ovate. Terminal buds are 6 to 10 millimeters long, seitständige slightly shorter. The needles usually grow to fifth, very rarely four or six in an initially 6-8 mm long, straw-colored to gray needle sheath which dandruff later separate and bend back to form a rosette at the base of the needle bundle. The rosette is maintained a long time, but drops out before the needles. The needles are erect to ascending. They are bent, stiff, 3 to 5 inches long and 0.9 to 1.3 millimeters wide. They are entire or have a narrow serrated edge. The needle end is blunt. The needles are gray and green, adaxially whitish or Glauk. Only the adaxial sides of each show four to five stomatal lines. It also forms two resin canals. The needles remain two to three years on the tree.
Cones and seeds
The pollen cones are initially yellowish and later yellowish brown, ovate -oblong and 5-8 millimeters long.
The seed cones grow near the ends of the branches, individually or in pairs on short, sturdy stems that are covered with pfriemlichen, caudate Lower leaves. Full-grown cones are closed almost round, open they are 3 to 4.5 inches long with diameters 3-5 centimeters and have a flattened base. There are usually 20 to 30 formed rarely to 40 seed scales. Near the base are infertile scales which open only slightly, the fertile scales open wide. They are irregularly shaped, often curved, thin and have one or two deep, cup-shaped indentations, which contain the seeds. The apophysis is slightly raised, rhombic to pentagonal, transversely keeled in outline, yellowish brown in color and often resinous. The umbo is dorsal and is slightly raised, rhombic in outline, armed with a small sting or unreinforced.
The seeds are brown, obliquely obovate, 5-7 mm long and 4-5 mm wide. The integument is from 0.8 to 1 mm thick. Seed wings absent if the seeds released from the seed scales.
Distribution, ecology and hazard
The natural range of Pinus culminicola is located in Mexico in the states of Coahuila and Nuevo Leon. It grows at altitudes of 3000-3700 meters, which includes the peaks of the mountains with. The habit is similar to the other midget pines in the mountain regions, such as the mountain pine ( Pinus mugo ) in Europe or the dwarf pine ( Pinus pumila ) in Asia. This is due to the adaptation to snow and sand storms and short growing seasons. The surface is mostly rocky and calcareous. Due to lack of weather stations near the summit, little is known about the climate, but there should be ample rainfall, partly in the form of snow. The distribution area is the hardiness zone 7 attributed with mean annual minimum temperatures -17.7 to -12.3 ° C (0 ° to 10 ° Fahrenheit ).
At Cerro Potosí, the highest peak of the Sierra Madre Oriental, the species forms extensive pure stands of growing close to each other copies. Absent you will also Pinus hartwegii, indicating that in this region in 3700 meters, the tree line has not been reached. In lower elevations in the Sierra La Marta in Coahuila it grows along with various species of oak (Quercus spp.), Representatives of the genus of bearberry ( Arctostaphylos ), the coffers flowers ( Ceanothus ), Agave ( Agave ), and various grasses. The flora on the Cerro La Viega and in the Sierra de Arteaga in Coahuila is similar, but to flourish representatives of fir (Abies ) and Douglas fir (Pseudotsuga). At Cerro Potosí pollen are released late in July, indicating a short growing season.
In the IUCN Red List Pinus culminicola is classified as endangered ( " Endangered "). The species is known only from a few summits. The best-known holdings are located on Cerro Potosí and cover several square kilometers, but they were greatly reduced by fires. Most of the other nine to ten populations are much smaller, the total stocks are highly scattered and copies are available only on the mountain tops, not in the intervening valleys. The biggest threat comes from fires in the long droughts, and fires have already destroyed parts of the stocks. The regeneration of stocks is slow. The fire frequency is likely to be increased by the increased occurrence of hikers and climbers on. Another danger comes from climate change, as the species is limited to a very narrow ecological niche. But at least the stocks on Cerro Potosí are located in a protected national park, and also destroyed the stocks regenerate slowly (as of 2012).
Systematics and history of research
Pinus culminicola is a species in the genus of pine (Pinus ), in which it is assigned to the subgenus strobus, Parrya section, subsection cembroides. The species was first described in 1961 by John William Andresen and John Homer Beaman in the Journal of the Arnold Arboretum. The genus name Pinus was already used by the Romans for several pine species. The specific epithet culminicola comes from Latin and means " grows at the summit ", referring to the area of distribution of the type
Aljos Farjon does not distinguish subspecies or varieties in his book A Handbook of the World's Conifers (2010). James E. Eckenwalder describes in Conifers of the World (2009) four varieties, which are assigned by Farjon partly different ways:
- Pinus culminicola bicolor var E.Little ) Eckenwalder: Farjon divided the taxon as Pinus cembroides var bicolor of the species Pinus cembroides to.
- Pinus culminicola var culminicola: The type - variety
- Pinus culminicola var locust ( M.Robert ) Silba: Farjon assigns the representatives of this variety also the variety Pinus cembroides var bicolor to.
- Pinus remota var culminicola ( E.Little ) Eckenwalder: Farjon sees the representative as a separate species Pinus remota.
Pinus culminicola var locust and Pinus culminicola var bicolor were classified in 2013 according to phenological and genetic studies as Pinus and Pinus discolor locust as a separate species.
Use
Pinus culminicola is not economically used even though the wood may locally as firewood is used. You could become important as an ornamental shrub for rockeries. Bushes in the Royal Botanic Garden Edinburgh, which were grown from seeds that have been found by Michael P. Frankis in 1991 and later thrive. Nevertheless, they are found only rarely in culture.