Papuacedrus papuana
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Branch and foliage of Papuacedrus papuana |
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| Scientific name of the genus | ||||||||||||
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| HL Li | ||||||||||||
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| Papuacedrus papuana | ||||||||||||
| ( F. Muell. ) HL Li |
Papuacedrus is a tree art from the family of the cypress family (Cupressaceae) and the only representative of therefore monotypic genus Papuacedrus . Two varieties are recognized, which differ in the shape of the leaves of young shoots and the size of the pollen cones . Their natural range is in New Guinea and the Moluccas . The wood is often used as construction wood for house building.
description
Papuacedrus papuana forms 20 meter high trees , rarely they reach heights of 50 meters. They are evergreen and single- sexed. The trunk is mostly monopodial , rather thin with a diameter of 60 centimeters at chest height . The bark is often twisted in a spiral, light brown, later gray, and flakes off in scales or strips. The branches of protected young trees are short and horizontal. Trees from mountain forests have upright, long branches and conical to umbrella-shaped crowns. Leafed branches are usually in dense compartments, end branches are usually slightly shorter and completely covered with flat leaves.
The leaves of the outer branches are scale-like and arranged either in whorls of four leaves or cross-opposed. The roof tile-like sheets are designed in two forms as flat sheets and edge sheets. The flat leaves are significantly narrower, about 1 millimeter long on older branches and up to 8 millimeters on young shoots. They have a rhombic to lanceolate shape, are keeled and sharply pointed. The edge leaves are lanceolate or oblong, flattened on both sides, usually 2 to 3 millimeters, on young shoots up to 20 millimeters long and with entire margins. The color of the leaves is shiny olive green to dark green, the stomata are whitish green.
The pollen cones stand individually at the ends of branches. They are 6 to 25 millimeters long, reach 2 to 3 millimeters in diameter and are cylindrical in shape. 8 to 30 shield-shaped microsporophylls with two to six, but mostly four, pollen sacs are formed per cones, which are arranged crosswise or in whorls of four. The seed cones are at or near the ends of twigs that are two to ten millimeters long. They have rhombic, pointed cone scales, are 8 to 18 millimeters long and have a diameter of 5 to 8 millimeters when closed. They are initially green and later change their color from whitish green and brown to dark black-brown. The cover scales grow in two cross-opposed pairs, the basal pair having a length of 4 to 7 millimeters and a width of 2 to 5 millimeters. It is widest and curved at the base. With a length of 7 to 17 millimeters and a width of 3 to 7 millimeters, the upper pair is significantly larger, elliptical and widest in the middle. Two to four red-brown, oblique-egg-shaped seeds are formed per cones , which are 2 to 5 millimeters long and 1 to 3 millimeters wide. Each seed has two thin seed wings on opposite sides. The larger wing is 4 to 7 millimeters long and 2 to 5 millimeters wide, the smaller one is often reduced to a strip, 1 to 2 millimeters wide and translucent yellowish brown.
Distribution and ecology
The natural range of the species is on the Moluccas and New Guinea . There you can find them at altitudes of 900 to 3600 meters, rarely from 620 to 3800 meters, in various forest zones from the tropical rainforest to the subalpine bush zone. It is most common in cloud and cloud forests at heights of 1500 meters to the tree line . In the tropical rainforest they are found scattered together with representatives of, for example, the casuarina ( Casuarina ), the pseudo-chestnut ( Castanopsis ), Cinnamomum , Engelhardia , Halfordia , Lithocarpus , Schizomeria and Xanthostemon . In higher areas it grows together with beeches ( Nothofagus ), Cryptocarya and cherry myrtle ( Eugenia ). Papuacedrus papuana forms together with the New Guinea araucaria ( Araucaria cunninghamii var. Papuana ) or more often with representatives of the resin disks ( Dacrydium ) and stone disks ( Podocarpus ) or Phyllocladus hypophyllus of conifers. These forests are often surrounded by fire-induced grassy areas with silver hair grass ( Imperata cylindrica ) and a border zone of heather plants (Ericaceae) and tree ferns (Cyatheales). The annual amount of precipitation in the distribution area is mostly high and depends on the season and reaches values of up to 4000 millimeters. At lower altitudes the species is mostly found on basic soils , at higher altitudes it is often found on acidic and water-soaked soils and the trees often grow stunted.
In the Red List of the IUCN is papuacedrus be deemed not at risk ( "Lower Risk / least concern"). It is pointed out, however, that a new check of the risk is necessary.
Systematics and research history
Papuacedrus is the only species in the thus monotypic genus Papuacedrus in the family of cypress plants (Cupressaceae). It was first described in 1889 by the German-Australian botanist Ferdinand von Mueller in the Transactions of the Royal Society of Victoria as Libocedrus papuana ( Basionym ). He placed the species in the Libocedrus genus, which is no longer recognized today . Li Hui Lin assigned the species to its own genus Papuacedrus in 1953 in the Journal of the Arnold Arboretum . The genus name is derived from Papua, an expression for New Guinea, on which the species occurs, and from cedrus for cedars ( Cedrus ). The specific epithet papuana also refers to New Guinea.
There are two varieties :
- Papuacedrus papuana var. Papuana : Young shoots of young trees have crescent-shaped, curved edge leaves protruding far from the base (up to 6 millimeters) with the tips pointing up or back. However, the surface leaves are also less protruding. The pollen cones are 6 to 15 millimeters long and have up to 16 cross-opposed or in whorls arranged microsporophylls. The variety occurs only in New Guinea. Although the wood is used extensively, there are still plentiful stocks and the occurrence is not endangered.
- Papuacedrus papuana var. Arfakensis (Gibbs) RJJohns : Young shoots of young trees only have edge leaves protruding up to 3 millimeters from the leaf base. The surface leaves are similar to those of older trees but are larger. The pollen tapers reach lengths of 15 to 25 millimeters and contain up to 30 microsporophylls arranged in whorls. The distribution area of the variety is on the Moluccas, the Vogelkop Peninsula and the Sudirman Mountains in New Guinea. The distribution area is very large but incoherent. The wood is also used extensively for building houses, especially in the area around the Paniai Lakes (formerly Wisselseen ) in New Guinea. It is therefore believed that stocks are declining. The largest stocks are probably still in the Arfak Mountains in New Guinea. The variety is therefore classified as “near threatened”.
The differences between the varieties in the morphology of the leaves appear only in young shoots of young trees. There are also transitional forms to the leaves of older trees. The distribution area of the two varieties overlaps in New Guinea, and the varieties can not be distinguished in many herbarium specimens without pollen cones. Therefore they are not recognized by some botanists, for example by Pieter van Royen .
use
The wood is often used as construction wood for house building, the fibrous bark is used in some areas for roofs and as insulation material. The species is rarely cultivated, but individual trees are planted in village dance areas. Few botanical gardens have representatives of Papuacedrus papuana .
proof
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 536-538 .
Individual evidence
- ↑ a b c d e Farjon: A Handbook of the World's Conifers , Volume 2, p. 536
- ↑ a b Farjon: A Handbook of the World's Conifers , Volume 2, p. 537
- ↑ Papuacedrus papuana in the endangered Red List species the IUCN 2011. Posted by: Conifer Specialist Group, 1998. Accessed December 24, 2011th
- ↑ a b Papuacedrus papuana. In: Germplasm Resources Information Network (GRIN). United States Department of Agriculture, accessed December 24, 2011 .
- ↑ Libocedrus papuana. In: Germplasm Resources Information Network (GRIN). United States Department of Agriculture, accessed December 26, 2011 .
- ↑ Papuacedrus papuana . Var arfakensis in the Red List of Threatened Species of the IUCN 2011. Posted by: S. Bachman, A. Farjon, M. Gardner, P. Thomas, D. Luscombe, C. Reynolds, 2007. Accessed December 26 2011.
- ^ Farjon: A Handbook of the World's Conifers , Volume 2, pp. 537-538
Web links
- Papuacedrus papuana. In: The Gymnosperm Database. Christopher J. Earle, December 12, 2010, accessed December 26, 2011 .