Amentotaxus formosana

Amentotaxus formosana

Amentotaxus formosana is a species of the genus Amentotaxus in the family of Yews ( Taxaceae ). The specific epithet refers to the origin of this kind, to Formosa the former name of Taiwan.

• 4.1 Notes and references

Description

Vegetative characteristics

Amentotaxus formosana grows as a evergreen tree or shrub, the plant height of 10 meters and a trunk diameter ( BHD) can reach up to 36 centimeters.

The leaves are arranged opposite constantly at a distance of about 6 mm at angles of 55 to 70 ° on the branch, but appear as two lines in a plane. The leaves are almost sessile ( subsessil ); If a petiole present it has a length of only 1 mm and is relatively thick. The leathery, dark green leaf blades are oblong lanceolate to falcate and 5 to 8.5 centimeters long and 0.5 to 1 centimeter wide. On the underside of leaves, the two are running parallel to the midrib, located about 2 millimeters wide Stomatabänder very close and clearly visible, each with about 30 rows. The blade tip is tapered oblong.

Generative features

Like the other species of the genus is dioecious getrenntgeschlechtig Amentotaxus formosana ( dioecious ), that is, male and female flowers are not related to an individual.

Male pins are located at one year and contains three to four branches ( often two or five) whorl, each of which can reach a length from 2.5 to 3 centimeters. Are located on the whorls in most four rows 20 to 30 Sporophyllstände. These are very narrow and irregularly decussate at the axis of the whorl and have a spherical shape and a diameter of 2.5 to 3 millimeters in size. A Sporophyllstand is composed of nine to twelve shield-shaped, round or triangular, 1.5 to 2 millimeters Sporophylle. At maturity they turn on and release the contained in 5-8 sporangia ( pollen sacs ), wingless pollen.

The female cones are located separately in the leaf axils and are bestielt up to 1.5 inches as well as spherical or ovoid. They can be up to 6.5 millimeters long until fertilization. The aril is reddish yellow when ripe and encloses the seed all the way up to the top. The reddish- purple seeds are oblong- ellipsoid or ovoid - ellipsoid with length of 2 to 2.5 inches and a width of 0.9 to 1.1 centimeters.

Occurrence and risk

Amentotaxus formosana is endemic in southern Taiwan. There he grows scattered at altitudes from 700 to 1500 meters in the tropical and sub-tropical rainforest, mostly in ravines or on cliffs. According to IUCN Amentotaxus formosana is threatened with extinction. Known are only four separate populations of no more than 250 mature trees. These are located in the counties of Taitung and Pingtung, on the mountains Dahanshan (大汉 山) in the " Dawushan Nature Reserve ", Kutzulunshan (姑子 仑 山), Chachayalaishan (茶茶 牙 顿 山) in the " Chachayalaishan Major Wildlife Habitats " and Lilungshan (楠 山).

Taxonomy

The first description of Amentotaxus formosana was made in 1952 by Hui -Lin Li in the Journal of the Arnold Arboretum, Volume 33, 2, pp. 196-197. He differentiated the hitherto with Amentotaxus Argotaenia regarded as monotypic genus in different ways, starting from the siled stocks and the different leaf shapes.

Swell

• Hsuan Keng: Aspects of morphology of Amentotaxus formosana with a note on the taxonomic position of the genus. In: Journal of the Arnold Arboretum. 50, No. 3, 1969, ISSN 0004-2625, pp. 432-445. Scanned online at botanicus.org.
• Liguo Fu, Nan Li, Robert R. Mill: Amentotaxus formosana. In: Wu Zheng -yi, Peter H. Raven (eds.): Flora of China. Volume 4: Cycadaceae through Fagaceae, Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1999, ISBN 0-915279-70-3, p 93
• Christopher J. Earle: Amentotaxus formosana. In: The Gymnosperm Database. December 12, 2010, accessed on 29 October 2011 ( English).
• Dawu Taiwan Amentotaxus Nature Reserve. November 15, 2005, accessed on 29 October 2011 ( English).