Mekong juniper
| Mekong juniper | ||||||||||||
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| Juniperus convallium | ||||||||||||
| Rehder & EH Wilson |
The Mekong juniper ( Juniperus convallium ) is a plant from the family of the cypress family (Cupressaceae). It is native to China.
description
The Mekong juniper grows as an evergreen tree , rarely as a shrub . The dense, straight or curved branches branch off from the branches. These are up to 1 millimeter thick and are usually pencil-shaped in cross-section, rarely rectangular in shape.
There are two different leaf shapes . The gray-green, scale-like leaves reach a length of 1.5 to 2 millimeters and a width of 0.8 to 1 millimeter. They are curved either inwards or outwards and have a resin gland near the base on the underside of the needle. They are cross-opposite or rarely in three whorls on the branches. The also gray-green, needle-shaped leaves are only found on young trees where they are cross-opposite or in whorls of three on the branches. They reach a length of 3 to 8 millimeters and are curved inwards on the top of the needle.
The Mekong juniper can be dioecious ( dioecious ) or monoecious ( monoecious ). The male cones have a diameter of 1.5 to 3 millimeters. They contain six to eight microsporophylls with two to three pollen sacs . The short stalked berry cones are egg-shaped to conical-egg-shaped or spherical with a length of 5 to 10 millimeters and a diameter of 5 to 6 millimeters. As they ripen, they are reddish brown to purple-black in color and can have a blue-green tint. Each of the cones bears a seed. With a diameter of 3 to 5 millimeters, the seeds are conical-spherical to flat-egg-shaped and may have a resin pit.
Distribution and location
The natural range of the Mekong juniper is in China. It encompasses the south of Qinghai Province , the northwest of Sichuan and the east of the Tibet Autonomous Region .
The Mekong juniper thrives at altitudes of 2200 to 4300 meters. The species is found in the mountainous regions where it grows mainly in coniferous forests.
Systematics
It was first described as Juniperus convallium in 1914 by Alfred Rehder and Ernest Henry Wilson in Plantae Wilsonianae an enumeration of the woody plants collected in Western China for the Arnold Arboretum of Harvard University during the years 1907, 1908 and 1910 , Volume 2, Number 1, page 62. A synonym for Juniperus convallium Rehder & EHWilson is Sabina convallium (Rehder & EH Wilson) WC Cheng & LK Fu .
The species is divided into up to two varieties :
- Juniperus convallium var. Convallium is the nominate form and occurs in the entire distribution area.
- Juniperus convallium var. Microsperma (WC Cheng & LK Fu) Silba : It occurs from West Sichuan to Southeast Xizang. Chemical studies support the distinction as an independent species Juniperus microsperma .
Hazard and protection
The variety convallium is classified as "low endangered" in the IUCN Red List . However, it is pointed out that a new check of the hazard is necessary. The microsperma variety is not assigned to any hazard category due to insufficient data.
swell
- Liguo Fu, Yong-fu Yu, Robert P. Adams & Aljos Farjon: Cupressaceae . Juniperus. In: Wu Zhengyi, Peter H. Raven & Hong Deyuan (eds.): Flora of China . Cycadaceae through Fagaceae. Volume 4. Science Press and Missouri Botanical Garden Press, Beijing and St. Louis 1999, ISBN 0-915279-70-3 , Juniperus convallium , pp. 75 (English, Juniperus convallium - online - this printed work is online with the same text).
Individual evidence
- ↑ a b c d e f Liguo Fu, Yong-fu Yu, Robert P. Adams & Aljos Farjon: Cupressaceae . Juniperus. In: Wu Zhengyi, Peter H. Raven & Hong Deyuan (eds.): Flora of China . Cycadaceae through Fagaceae. Volume 4. Science Press and Missouri Botanical Garden Press, Beijing and St. Louis 1999, ISBN 0-915279-70-3 , Juniperus convallium , pp. 75 (English, Juniperus convallium - online - this printed work is online with the same text).
- ↑ a b c Juniperus convallium . Var microsperma in the Red List of Threatened Species of the IUCN 2011. Posted by: Farjon, A. (RBG Kew), 2007. Accessed 10 May 2012.
- ↑ a b Juniperus convallium at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed May 10, 2012.
- ↑ Rafaël Govaerts (ed.): Juniperus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved March 27, 2019.
- ↑ Juniperus convallium . Var convallium in the endangered Red List species the IUCN 2011. Posted by: Conifer Specialist Group, 1998. Accessed 10 May 2012.