Agathis borneensis
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Agathis borneensis |
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| Warb. |
Agathis borneensis is a species ofthe Araucaria family (Araucariaceae). It is native to southeast Asia.
description
Agathis borneensis grows as an evergreen tree that can reach heights of 50 to 55 meters and diameters of up to 3.5 meters at chest height . When the trees are fully grown, the trunk is unbeaten up to a height of 20 to 30 meters and then ends in a widely spreading crown . The trunk bark is very variable. It is gray, light brown to black in color, curled or thinly scaly or rough. Parts of the bark peel off.
The thick and leathery, light green leaves are more or less elliptical with a length of 2.5 to 14 centimeters, although their shape can vary greatly even on a single tree. They are between three and ten times as long as they are wide. Younger trees usually have larger leaves than old trees.
The single male cones, which are dark brown at the time of flowering, are on a 1 to 10 millimeter long stem and are oval-cylindrical in shape with a length of 3 to 4 centimeters and a thickness of 1.4 to 1.8 centimeters. They contain microsporophylls with four to ten pollen sacs .
The elliptical to spherical, single female cones are 10 to 13 centimeters tall and are resinous. They stand on a thick stem, are initially green and turn brown as they mature.
Distribution and location
The natural range of Agathis borneensis includes the Malay Peninsula below 10 ° north latitude and the islands of Borneo and Sumatra .
The species grows in tropical rainforests and kerangas on sandy or peaty soils at altitudes of up to 1200 meters. There it occurs in pure stands, but often together with other conifer species such as Falcatifolium falciforme , Nageia wallichiana , Sundacarpus amarus and various types of stone slices ( Podocarpus ).
Agathis borneensis is classified as "critically endangered" in the IUCN Red List . The overexploitation of forests is cited as the main risk factor. In the past, the population of the species has shrunk by a good half and is still considered to be in decline.
Systematics
Agathis borneensis is assigned to the Agathis section within the genus of the Kauri trees ( Agathis ) .
The first description as Agathis borneensis was made in 1900 by Otto Warburg in Monsunia, Contributions to the knowledge of the vegetation of the South and East Asian monsoon area , Volume 1, page 184. Synonyms for Agathis borneensis Warb. are Agathis beccarii Warb. Meijer Drees , Agathis beckingii , Agathis latifolia Meijer Drees , Agathis macrostachys Warb. and Agathis rhomboidalis Warb. Also agathis endertii is considered by some authors because of minor morphological differences to Agathis borneensis considered a synonym of that kind.
Due to the great similarity with Agathis dammara , Agathis borneensis was often confused with this species in the past.
swell
- Christopher J. Earle: Agathis borneensis. In: The Gymnosperm Database. www.conifers.org, April 17, 2013, accessed December 27, 2013 .
Individual evidence
- ↑ a b c d e f Christopher J. Earle: Agathis borneensis. In: The Gymnosperm Database. www.conifers.org, April 17, 2013, accessed December 27, 2013 .
- ↑ a b c d Agathis borneensis in the endangered Red List species the IUCN 2013. Posted by: A. Farjon, 2012. Accessed December 27, 2013.
- ↑ Agathis borneensis at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed December 27, 2013.
- ↑ Agathis borneensis. In: The Plant List. www.theplantlist.org, accessed December 27, 2013 .
