Amentotaxus poilanei
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| ( Ferré & Rouane ) DK Ferguson |
Amentotaxus poilanei is a plant from the genus of amentotaxus ( Amentotaxus ) within the family of yew plants (Taxaceae). This endemic occurs only in a small area in Vietnam. Some authors doubt whether the classification as a separate species is justified; the populations are oftenassigned to Amentotaxus yunnanensis .
description
Appearance
Amentotaxus poilanei grows as a large, evergreen tree , stature heights of up to 20 meters and trunk diameters ( breast height diameter ) of up to 1 meter. The trunk bark is brown, initially smooth and scaly in larger trunks. It flakes off in thin layers. The branches are spread out or rising. The needled branches grow opposite at an angle of 25 to 60 degrees on the branches. They are ascending or spread out, have an angular cross-section and alternating grooves that each connect two needles. They are green in the first year and turn yellowish brown in the following years.
Buds and needles
The vegetative buds are ovate and have ovoid-triangular, keeled, pointed bud scales.
The needles grow in two lines and are at an angle of 50 to 70 degrees from the branch. They are short-stalked needles, with a length of usually 5 to 8 (3 to 9) centimeters and a width of 4.3, usually 5 to 8.5 millimeters, obverse-lanceolate or linear, usually straight or sometimes light or stronger curved sickle-shaped. The base narrows more or less continuously, the needle tapers conically to the pointed or blunt tip. The edge of the needle is rolled down. The needles are dark green, leathery, and they form sclerenchymal cells , which make the top of the needle speckled and wrinkled. The underside of the needle shows two white or cream-colored-gray, thickly covered with white wax stomata from numerous scattered stomata, which are separated from each other by the midrib and from the edge of the needle by two green bands. The stomata are 1.5 times wider than the green marginal strips. The midrib is significantly raised on the top of the needle and lies in a 0.5 millimeter wide, shallow furrow reaching to the tip. On the underside of the needle, the midrib is raised at least near the base of the needle and 1 to 1.8 millimeters wide.
Cones and seeds
The pollen cones are arranged in 2.5 to 4.5 centimeter long bunches of 8 to 12 pairs of cones. Usually three to four grapes grow together from a large lateral or almost terminal bud; there are rarely individual grapes. The cones are round or egg-shaped with a length of 3 to 4 millimeters. The eight to eleven microsporophylls are shield-shaped and usually carry four to six and sometimes up to eight pollen sacs from three .
The seed- bearing structures grow individually in the axils of the needles near the ends of needled branches on a thin, downward-curved, 1 to 2 centimeter long stem with about eight cross-opposed, keeled cover scales, which enclose the individual, terminal ovule . The ovules are only known when they are immature.
Occurrence
This endemic occurs only in the Vietnamese in Kon Tum province on Ngoc Linh . Amentotaxus poilanei grows as a large tree in the evergreen rainforest in the mountains at an altitude of 1800 to 2300 meters. It grows scattered, but locally common, with deciduous trees and possibly Nageia wallichiana as the only conifer. There is very frequent rainfall, the annual rainfall is at least over 3000 millimeters. The climate is cool due to the almost constantly closed cloud cover.
Hazard and protection
In the IUCN Red List of IUCN is Amentotaxus poilanei given the small size of the known distribution area as "endangered" (= "Vulnerable") out. There is only one site at Ngoc Linh with fewer than 1000 fully grown trees. Further research is needed to determine if there are additional stocks. No threat is known in 2010, but the development of roads and the conversion of forests into arable land could quickly change the classification to “critically endangered”. Parts of the stocks are in protected areas.
Systematics and Etymology
It was first described in 1978 by Ferré and Rouane in Travaux du Laboratoire Forestier de Toulouse , Tome I, T.1 (9.1), page 3 as Amentotaxus yunnanensis var. Poilanei ( Basionym ) and thus as a variety of the species Amentotaxus yunnanensis . Different lengths and widths of the needles were given as a distinguishing feature from the type variety. In 1990 Ferguson recognized her in the Bulletin du Muséum National d'Histoire Naturelle - Section B, Adansonia. sér. 4, Botanique Phytochimie , Volume 11, 3, page 316. under the name Amentotaxus poilanei species status to. He assumed that the length and the width of the needles are not very informative with regard to the classification of the taxon due to the large range of variation, and instead examined the ratio of length and width of the needles. He was able to show that Amentotaxus poilanei has narrower needles than Amentotaxus yunnanensis , and that there is less overlap in this characteristic than when length and width are given separately. He also found other distinguishing features in the needles, such as the thinner resin channels and a different shape of the needle rim. According to Ferguson, Amentotaxus poilanei is more similar to Amentotaxus formosana . As with Amentotaxus hatuyenensis , recognition as a separate species is doubtful. The classification is also made more difficult by the fact that no mature female ovules are known. In 2009, James Eckenwalder sees the name Amentotaxus poilanei only as a synonym of Amentotaxus yunnanensis var. Formosana and thus does not give the specimens the status of a variety.
Amentotaxus poilanei is a species of the genus of the catkins ( Amentotaxus ). The generic name Amentotaxus is derived from the Latin words amentum for “throwing belt” but also botanically “kitten” and taxus for “yew”. He thus refers to the cluster-shaped arrangement of the pollen cones and corresponds to the German name "Kitteneibe". The specific epithet poilanei honors the French plant collector Eugène Poilane (1888–1964), who found the type specimens.
use
Usage of Amentotaxus poilanei not known. The size of the trees would allow the wood to be used to make furniture, tools and other things, but the stocks are too remote. Amentotaxus poilanei was not in culture in 2010.
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 1 . Brill, Leiden-Boston 2010, ISBN 978-90-04-17718-5 , pp. 168, 174-175 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 146 .
Individual evidence
- ↑ a b Christopher J. Earle: Amentotaxus poilanei. In: The Gymnosperm Database. www.conifers.org, March 1, 2019, accessed on May 13, 2019 .
- ↑ a b c d e f Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 174
- ↑ a b c d Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 175
- ↑ a b Amentotaxus poilanei in the endangered Red List species the IUCN 2013. Posted by: Nguyen, TH Nguyen, Phan KL, QH Nguyen, P. Thomas, 2010. Retrieved on 13 May of 2019.
- ↑ Amentotaxus poilanei at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed on May 13, 2019.
- ↑ Amentotaxus poilanei in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved May 13, 2019.
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 1, pp. 174-175
- ↑ James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 146 .
- ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 56 (reprint from 1996).
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 168