Pinus luchuensis
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Pinus luchuensis is an evergreen conifer from the genus of pine ( Pinus ) with 10 to 15 centimeter long needles and 4 to 5.5 centimeter long seed cones. The distribution area is on the Ryūkyū Islands of Japan and extends from sea level to 700 meters above sea level. Pinus luchuensis is very wind-tolerant and tolerates salty air and sea spray well. The wood is hardly used economically, but the species is also used to stabilize coastal sand dunes outside of their natural range.
description
Habitus
Pinus luchuensis is an evergreen tree , 15 to sometimes 20 meters high, with a trunk diameter of up to 60 centimeters. The trunk bark is gray-brown, rough and scaly and breaks in the lower part into large plates with furrows up to 1 centimeter deep and 1.5 to 4 centimeters wide. The bark of young trees and the crown branches is thinner, smooth and grayish. The cork pores are inconspicuous. Only a few first-order branches are formed, which are mostly long and horizontal, with the trees in their natural location mostly being shaped by the wind. Branches of a higher order are ascending and are densely packed. In their natural environment they form a flat, dome-shaped crown. Needle branches are bare, more or less smooth and gray.
Buds and needles
The buds are ovate-conical, 10 to 15 millimeters long, 5 to 7 millimeters wide and resinous. The bud scales are pressed, orange or rust-brown. The needles grow in pairs in a permanent, thin basal needle sheath about 10 millimeters long. The needles are dark green, straight or slightly curved, 10 to 15 centimeters long and 0.7 to 1 millimeter thick with a semicircular cross-section, thin, flexible, slightly twisted with finely sawn edges and a pointed end. Two vascular bundles and two or three central resin channels are formed for each needle . There are fine stomata lines on all needle sides .
Cones and seeds
The pollen cones grow spirally arranged in groups. They are 1.5 to 2 centimeters long, initially tinged with yellow and red and later reddish brown. The seed cones grow singly or sometimes in pairs on short stalks. They are 4 to 5.5 centimeters long, narrowly ovate when closed and 2.5 to 3 centimeters in diameter when opened. The seed scales are dull brown, thin woody, stiff, elongated, straight or when opened, slightly bent back, about 2 inches long and 1 cm wide in the center of the cone. The apophysis is shiny brown, slightly raised, with a rhombic or rounded circumference and keeled transversely. The umbo is small, pyramidal and armed with a sharp, pointed thorn. The seeds are ellipsoidal-egg-shaped, 4 to 5 millimeters long and slightly flattened. The seed wing is lanceolate, 10 to 15 millimeters long and persistent.
Chromosome number
The number of chromosomes is 2n = 24.
Distribution, ecology and endangerment
The natural range of Pinus luchuensis is on the Okinawa Islands and Amami Islands , which are part of the Ryūkyū Islands of Japan. Pinus luchuensis is a marine species that occurs on the coast of Okinawa and other islands up to an altitude of 700 meters. It grows on sand dunes, rocky foothills and hills often near the coast in locations exposed to the wind. The species is very tolerant of salty air and salt water spray, but also thrives in forestry conditions without wind and far from the sea. Under natural conditions it has hardly any competitors and mostly forms open, pure stands with only a small undergrowth of grasses and bushes, which stabilize the sand. The distribution area is assigned to winter hardiness zone 9 with mean annual minimum temperatures of −6.6 to −1.1 ° C (20 to 30 ° F).
In the Red List of the IUCN is Pinus Luchuensis be deemed not at risk ( "Lower Risk / least concern"). However, it should be noted that a reassessment is pending.
Systematics and research history
Pinus luchuensis is a species from the genus of pines ( Pinus ), in which it is assigned to the subgenus Pinus , section Pinus and subsection Pinus . It was published in 1894 by Heinrich Mayr in About the Pines of the Japanese Empire. Supplements to the Botanisches Centralblatt 58, pages 148-151 , scientifically described for the first time . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet luchuensis is derived from Luchu , the former English name of the Ryūkyū Islands.
Pinus luchuensis is the Japanese representative of a group of three closely related and very similar species to which Pinus taiwanensis from Taiwan and Pinus hwangshanensis from continental China are counted. These species are either often directly attributed to Pinus luchuensis or are considered varieties or subspecies. Pinus luchuensis differs from Pinus taiwanensis in that it has longer needles, fewer resin channels (two to three instead of four to seven), shorter cones and thinner bark.
use
Pinus luchuensis is only of minor local importance as a supplier of wood. Due to the tolerance to wind and salty air, it is used to stabilize coastal dunes not only on the Ryūkyū Islands, but also in other areas of Japan and Taiwan. The species is not used as an ornamental plant; no cultivars are known.
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literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 703-704 .
- Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 487 (reprint from 1996).
Individual evidence
- ↑ a b c d e f Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 704
- ↑ a b c d e f Christopher J. Earle: Pinus luchuensis. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed March 3, 2013 (English).
- ^ Tropicos. [1]
- ↑ Pinus luchuensis in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 2000. Accessed March 3, 2013.
- ↑ Pinus luchuensis. In: Germplasm Resources Information Network (GRIN). United States Department of Agriculture, accessed March 3, 2013 .
- ↑ To be precise: Etymological dictionary of botanical plant names. P. 487
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 703
Web links
- Pinus luchuensis. In: The Plant List. Retrieved March 3, 2013 .