Amentotaxus poilanei
Amentotaxus poilanei is a large coniferous tree of the genus kitten yew ( Amentotaxus ). The natural range of the species is located in Vietnam. It is listed in the IUCN Red List as endangered. Whether the classification is justified as a separate species, is doubted, the trees are often associated Amentotaxus yunnanensis.
- 6.1 Literature
- 6.2 Notes and references
Description
Appearance
Amentotaxus poilanei grows as evergreen, up to 20 feet tall with trunk diameters of up to 1 meter ( diameter at breast height ). The Stammborke is brown, initially smooth and scaly at larger strains. She peels off in thin layers. The branches are spread or ascending. The needled branches growing against constantly at an angle of 25 to 60 degrees on the branches. You are ascending or spread, have a polygonal cross-section and alternating grooves that connect two needles. You are in the first year green and turn yellowish brown in the following years.
Buds and needles
The vegetative buds are ovate ovate - triangular, keeled, pointed bud scales.
The needles grow in two rows and are starting at an angle of 50 to 70 degrees from the branch. They are short-stalked, lanceolate or linear - runs, mostly straight or sometimes slightly or strongly curved sickle-shaped, from 3 but usually 5-8, sometimes up to 9 inches long and from 4.3 usually 5 to 8.5 millimeters wide. The base narrows more or less continuously, the needle is tapered to acute or obtuse tip together. The needle edge is rolled down. The needles are dark green, leathery and they make sclerenchyma cells, which spotted the needle top and makes wrinkled. The needle bottom shows two white or cream - gray, thickly covered with white wax stomatal strips from numerous stomata scattered distributed, which are separated by the midrib of each other and by two green bands from the needle edge. The stomatal strips are 1.5 times wider than the green border strip. The midrib is significantly increased on the needle top and is located in a 0.5 -millimeter-wide, reaching to tip, shallow furrow. On the underside of the needle midrib is increased at least close to the needle base and 1 to 1.8 millimeters wide.
Cones and seeds
The pollen cones are arranged in 2.5 to 4.5 cm long racemes of 8-12 Zapf pairs. Most grow three to four grapes composed of a large axillary or terminal bud almost, rarely there are also individual grapes. The cones are round or egg-shaped and 3-4 millimeters long. The eight to eleven Mikrosporophylle are shield-shaped and wear each from three usually four to six, and sometimes up to eight pollen sacs.
The seed -bearing structures grow near the ends benadelter branches individually in the axils of the needles on a thin, downward curved, 1-2 cm long stem arranged decussate with about eight, keeled bracts enclosing the single, terminal ovule. The ovules are known only in the immature state.
Distribution and ecology
The natural range of Amentotaxus poilanei located in Vietnam in the province of Kon Tum Ngoc Linh on. The species grows as a large tree in the evergreen rain forest in the mountains at an altitude 1800-2300 meters. It grows scattered, but locally common, along with deciduous trees and possibly Nageia wallichiana as the only conifer. There are very frequent rainfall, the annual rainfall is at least about 3000 millimeters. The climate is cool by the almost constantly closed cloud cover.
Threats and conservation
In the IUCN Red List Amentotaxus poilanei is listed as endangered ( " Vulnerable " ) due to the small size of the known distribution area. There is only one site on the Ngoc Linh with fewer than 1,000 full-grown trees. Further studies are necessary to determine whether there are more stocks. Currently (as of 2010 ) is not aware of any threat, but " threatened with extinction " ( " Critically Endangered " ) the classification could about by the expansion of roads and by converting forests to cropland to quickly change. Parts of the stocks are in protected areas.
Systematics and etymology
Amentotaxus poilanei is a species in the genus of yew kitten ( Amentotaxus ). It was first described in 1978 by Ferré and Rouane in Travaux du Laboratoire de Toulouse Forestier as Amentotaxus yunnanensis var poilanei ( basionym ) and thus assigned as a variety of the species Amentotaxus yunnanensis. The distinguishing feature of the type - variety of different lengths and widths of the needles were given. 1990 Ferguson saw her in the Bulletin du Muséum National d' Histoire Naturelle species status. He asserted that provide little information regarding the classification of the taxon, the length and the width of the needles due to the large range of variation, and instead examined the ratio of length and width of the needles. He could show that Amentotaxus poilanei narrower needles has yunnanensis as Amentotaxus, and there is less overlap in this feature as if the length and width are specified separately. He also found other distinguishing factors in the needles such as the thinner resin channels and a different form of needle edge. According to Ferguson, the type is more like formosana Amentotaxus. As with Amentotaxus hatuyenensis here is the recognition doubtful as a separate species. The classification is also made more difficult because no mature female ovules are known. James Eckenwalder sees the name Amentotaxus poilanei only as a synonym of Amentotaxus yunnanensis var formosana and the representatives are therefore not the status of a variety.
The genus name is derived from the Latin Amentotaxus amentum for " throwing belt " but also botanical "Kitten " from and taxus, the Latin name of " yew ". He thus refers to the grape-like arrangement of the pollen cones and corresponds to the German name " Kätzcheneibe ". The specific epithet honors poilanei Eugène Poilane (1888-1964), which has the type specimens have been found.
Use
The use of the type is not known. The size of the trees would allow the use of the wood, resulting in furniture, tools and other could be made, but the stocks are too remote. The species is currently (as of 2010 ) is not in culture.