Pinus lumholtzii
Pinus lumholtzii is an evergreen coniferous tree of the genus pine (Pinus ), usually with 20 to 30 centimeters long, hanging and growing in groups of three needles and 3.5 to 5.5 cm long seed cones. The natural range is located in the Sierra Madre Occidental in Mexico. The species is not endangered. It is hardly used economically and horticulturally used rarely.
- 5.1 Literature
- 5.2 Notes and references
Description
Appearance
Pinus lumholtzii grows as evergreen, up to 20 meter high tree. The trunk is straight and reaches a diameter at breast height of 50 to 70 centimeters. The Stammborke is thick, very rough and scaly, dark brown to gray- brown and divided into irregular, elongated plates and deep, wide, vertical cracks. The branches are horizontal or ascending, branches of higher order, that is not the main branches are thin, flexible and overhanging. The tree crown is broad, dome-shaped and mostly open. Young shoots are glabrous, at first covered with a layer of wax and later reddish brown and gray.
Buds and needles
The vegetative buds are ovate - conical, pointed and resinous. Terminal buds are about 15 millimeters long with a diameter of 8 millimeters, seitständige buds are smaller. Trained as bud scales Lower leaves are reddish brown, trockenhäutig, pfriemförmig and up to 10 millimeters long. The needles grow in threes, only in exceptional cases two or four, in an initially from 20 mostly 25 to 35 mm long needle sheath. The needle sheath consists of about ten reddish brown scales, which separate soon and form at the base of a clump and later fall off completely. The needles are very hanging, soft, thick, light green, 20 to 30 centimeters, rarely over 15 and up to 40 or more inches long and 1.2 to 1.5 mm, rarely only 1.0 millimeters thick. You spend two years on the tree. The needle edge is finely serrated, pointed the end. On all sides there are needle clearly visible stomatal lines. There are four to eight to ten rarely formed resin canals.
Cones and seeds
The pollen cones grow in small groups. They are initially pink, later yellow, cylindrical and grown 2 to 3 inches long with diameters of about 5 millimeters. The seed cones grow on the sides or near the ends of branches, usually solitary, rarely in whorls in twos or threes to 10 to 15 millimeters long, curved stems that break easily and then remain on the pin. Mature cones are closed narrowed ovate to ovate, ovate to ovate open - pointed, usually from 3 3.5 to 5.5 and rarely up to 7 inches long and from 2.5 usually 3 to 4.5 inches wide. The most often from 60 to 80 and 50 to 100 seed scales are thick woody, more or less rectangular, open wide, lying near the base of the scales are closed or have even grown. The apophysis is thickened along the outer rim, indistinct, transversely keeled, with rhombic or pentagonal outline, ocher or reddish brown. The basal apophysis shed is bumpy. The umbo is reinforced flat or slightly above, and with a small, soon falling sting. The seeds are wrong obovate, slightly flattened, 3-5 mm long, spotted dark brown and black. The seed wings are usually from 8 10 to 14 millimeters long, 4-6 mm wide, yellowish or grayish brown.
Distribution, ecology and hazard
The natural range of Pinus lumholtzii is located in Mexico in the Sierra Madre Occidental in the states of Chihuahua, Sinaloa, Durango, Nayarit, Jalisco, Zacatecas, Aguascalientes and Guanajuato.
It grows at altitudes from 1700 to 2600 meters, rarely also from 1500 and up to 2900 meters above sea level to the lower and mid-level slopes of the Sierra Madre. The distribution area is the hardiness zone 9 attributed with mean annual minimum temperatures between -6.6 ° and -1.2 ° C (20 ° to 30 ° Fahrenheit ). The annual rainfall is about 500 to 600 millimeters, except in the wettest and driest areas and falls mostly as summer rain. It grows mostly in mixed forests of pine and oak trees. Other pines often lumholtzii occurring with Pinus are leiophylla Pinus, Pinus arizonica, Pinus douglasiana, Pinus and Pinus teocote oocarpa. In wetter areas, they are found together with Pinus ayacahuite and Pseudotsuga menziesii, Pinus may occur in drier cembroides together.
The IUCN Red List is classified as Pinus lumholtzii not endangered ( " Lower Risk / least concern "). It is noted, however, that a reassessment is necessary.
Systematics and history of research
Pinus lumholtzii is a species in the genus of pine (Pinus ), in which it is assigned to the subgenus Pinus, section and sub-section Trifoliae Austral. It was described in 1895 by Benjamin Lincoln Robinson and Merritt Lyndon Fernald in the Proceedings of the American Academy of Arts and Sciences for the first time scientifically. The genus name Pinus was already used by the Romans for several pine species. The specific epithet honors lumholtzii the Norwegian naturalist Carl Lumholtz (1851-1922), who led the scientific expedition on which the type specimen was found.
Pinus lumholtzii similar by their drooping needles of Pinus patula significantly larger, which occurs in the wetter areas in eastern and southern Mexico. However, more detailed analyzes, for example, the falling leaf sheaths suggest a closer relationship with Pinus leiophylla.
Use
Due to the scattered occurrence in mixed forests, the species has economically of little significance. However, it was overexploited in some areas along with other pines because of the wood. The species is in Mexico after their hanging needles as " pino triste" (translated as " sorrow pine " ) is known, but is still hardly used horticulturally.