Amentotaxus argotaenia

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Amentotaxus argotaenia
Branch of Amentotaxus argotaenia

Branch of Amentotaxus argotaenia

Systematics
Subdivision : Seed plants (Spermatophytina)
Class : Coniferopsida
Order : Conifers (Coniferales)
Family : Yew family (Taxaceae)
Genre : Kitten slices ( Amentotaxus )
Type : Amentotaxus argotaenia
Scientific name
Amentotaxus argotaenia
( Hance ) Pilg.

Amentotaxus argotaenia is a shrub-like or small tree-growing conifer from the genus of the catkins ( Amentotaxus ). Adistinction is made betweentwo varieties . The natural range is in the south of China, on Taiwan, in Laos and Vietnam. The species is classified as low endangered inthe IUCN Red List . However, the variety Amentotaxus argotaenia var. Brevifolia is considered critically endangered.

description

Appearance

Amentotaxus argotaenia grows as an evergreen shrub or small tree up to 7 meters high . The trunk reaches a chest height diameter of mostly up to 20, rarely up to 50 centimeters. The trunk bark is smooth, initially reddish brown and later turns light or dark gray. It flakes off in thin flakes. The few branches are spread out or ascending. The leafy branches grow ascending or almost upright, opposite and at an angle of 25 ° to 70 ° on the branch. They are broadly rectangular to oblong-elliptical in outline, 4.5 to 8 inches long and 8 to 15 inches wide. The cross-section of the axis is square to almost stem-round. The bark is green in the first year in the second and third year it changes color from greenish yellow to orange-brown.

Buds and needles

The vegetative buds are conical and have egg-shaped-triangular, pointed bud scales.

The needles grow in two lines and are usually at an angle of 45 ° to 90 °, rarely up to 95 ° from the branch. They are almost sitting or stalked up to 3 millimeters long. The needles are linear or linear-lanceolate, from 2 mostly 3 to 9 and rarely up to 11 centimeters long, 5 to 11 millimeters wide, crescent-shaped or almost straight. The base is asymmetrical and wedge-shaped to tapering to a point. The edge of the needle is rolled down flat or very narrowly. The tip is darker, calloused and rounded to sharply triangular. The first four or more needles located at the base of the branch have a blunt point, the other needles are often pointed. The needles are leathery and form sclerenchymal cells , which means that fresh needles are spotted and dry ones are wrinkled. The top of the needle is dark green. The underside shows two white stomata bands with numerous, scattered stomata, which are separated from each other by the central rib and from the edge of the needle by two green bands of about the same width. The midrib is significantly raised on the top of the needle, 0.8 to 1 millimeter wide and lies in a shallow groove. On the underside of the needle, it is almost flat and 1.2 to 1.5 millimeters wide.

Cones and seeds

The pollen cones are arranged in 1.5 to 6.5 cm long bunches of 10 to 12 pairs of cones. Usually two to four of the brevifolia variety grow to 10 grapes together on one branch. The cones are egg-shaped, 3 to 3.5 millimeters long and have a diameter of 2.3 to 3.5 millimeters. The six to eight microsporophylls are shield-shaped and each carry two to five, but mostly three pollen sacs .

The structures carrying the seeds grow individually in the axils of the needles near the ends of the branches on a thin, downwardly curved, 1.5 to 2 centimeter long stalk. Six to eight, sometimes up to ten cruciform, keeled cover scales surround a single, terminal ovule . At pollination time, a pollination drop is formed. The seed is surrounded by an ellipsoidal to narrow obovate, 20 to 26 millimeter long and 10 to 13 millimeter diameter, smooth aril , which has a spiky end and a shiny light red color when ripe. The actual elongated or ellipsoidal seed is much smaller with a length of about 15 millimeters and a diameter of about 7 millimeters. It has a small, spiked end.

The pollen is released in April and the seeds ripen in October.

Distribution and ecology

The natural range of Amentotaxus argotaenia is in China in the provinces of Chongqing and Fujian , in the south of Gansu , in Guangdong , Guangxi and Guizhou , in the west of Hubei , in Hunan and Jiangsu , in the northwest of Jiangxi , in Sichuan , in the south of Zheijang and in the southeast of the Tibet Autonomous Region , on the island of Taiwan , in Laos and in the north of Vietnam in the Hà Giang province . The species is widespread and grows on limestone, sandstone, slate and granite in gorges, on steep slopes and rock faces, on mountain peaks and ridges and in mountain forests along shady rivers at heights of 600 to 1100 meters. The distribution area is assigned to winter hardiness zone 8 with mean annual minimum temperatures between −12.2 and −6.7 ° C (10 to 20 ° F ). The socialized species differ depending on the subsoil. On the type of lime grows with Pinus kwangtungensis , various species of the genus Nageia , with the Oleanderblättrigen Podocarpus ( Podocarpus neriifolius ), Podocarpus pilgeri , the broad-leaved Podocarpus ( Podocarpus macrophyllus ) and with the Chinese yew ( Taxus chinensis ). On acidic subsoil, the species is found together with Amentotaxus yunnanensis , various species of head yams ( Cephalotaxus ) and deciduous trees and deciduous shrubs such as types of magnolias ( Magnolia ), oaks ( Quercus ) and rhododendrons ( Rhododendrons ) in montane, evergreen forests.

Hazard and protection

In the Red List of the IUCN is amentotaxus argotaenia out ( "Near Threatened") at risk as low. The total population has decreased by around 20 to 29 percent in the last 75 years (as of 2010). Despite the large distribution area, the habitat deteriorates in the entire area, for example by converting the forests into agricultural areas. In addition, the growth rates are low, the seeds are slow to spread, and are often eaten by rats. Most stocks are small and isolated from each other, and they continue to decline. However, some populations reside in protected areas.

Systematics and Etymology

Amentotaxus argotaenia is a species from the genus of the catkins ( Amentotaxus ). It was in 1883 by Henry Fletcher Hance as Podocarpus Argotaenia ( Basionym ) in the Journal of Botany, British and Foreign firstdescribed , so to the genus Podocarpus ( Podocarpus provided). Robert Knud Friedrich Pilger presented this species as Amentotaxus argotaenia (Hance) Pilg in 1916 . into the newly established genus Amentotaxus . More synonyms of Amentotaxus argotaenia (Hance) Pilg. are Amentotaxus cathayensis  H.L.Li , Cephalotaxus argotaenia  (Hance) Pilg. , Nageia argotaenia  (Hance) Kuntze , Nageia insignis  (Hemsl.) Kuntze and Podocarpus insignis  Hemsl.

The generic name Amentotaxus is derived from the Latin amentum for “throwing belt” but also botanically “kitten” and from taxus , the Latin name for “yew”. He thus refers to the cluster-shaped arrangement of the pollen cones. The specific epithet argotaenia is derived from the Greek argyr for "silver" and taenia for "ribbon". It describes the two stomata on the underside of the needles.

There are two varieties :

  • Amentotaxus argotaenia var. Argotaenia : The needles are 3 to 11 centimeters long and 6 to 11 millimeters wide. The pollen cones are arranged in groups of two to four, sometimes up to five, and rarely grow individually. They are 5 to 6.5 inches long. The seed with the aril is 20 to 26 millimeters long and has a diameter of 10 to 13 millimeters. The distribution area coincides with the information on the species. Like the species, the variety is listed by the IUCN as "Near Threatened". In Vietnam it was very numerous locally, in Hong Kong the population, if it still exists, consists of 20 specimens. In southern China, the variety is widespread and common. However, stocks are falling.
  • Amentotaxus argotaenia var. Brevifolia K.M. Lan & FHZhanG : The needles are 2 to 3.7 centimeters long and 5 to 7 millimeters wide. The pollen cones are arranged in groups of up to ten and 1.5 to 5.5 inches long. The seed, together with the aril, is about 20 millimeters long and about 10 millimeters in diameter. The distribution area is in the southeast of Guizhou in Libo County . The variety grows on steep, karst slopes and mountain ridges at an altitude of about 900 meters. It is listed as critically endangered by the IUCN. The range is very small with less than 5 square kilometers and probably also the number of individuals, although this is not exactly known. According to the Chinese Red List, there are fewer than 50 adult specimens. Even so, trees continue to decline as trees are felled and forests turned into agricultural land.

James Eckenwalder counts the species Amentotaxus assamica as a variety Amentotaxus argotaenia var. Assamica (DKFerguson) Eckenwalder also to Amentotaxus argotaenia . However, this assignment is not used in the Flora of China , Aljos Farjon or the IUCN.

use

Tools and furniture are made from the wood and it is used for turning . The species is cultivated in China and was introduced into Europe from Hong Kong . It is used as an ornamental shrub , but only in warmer areas. In China, the species is also used as a bonsai . The seeds are rich in oils and surrounded by a striking aril. It is being investigated whether it can be used to produce anti- cancer drugs , as for various yew species ( Taxus spp.) (Status 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. 168-170 .
  • James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 145 .
  • Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . Volume 4: Cycadaceae through Fagaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1999, ISBN 0-915279-70-3 , pp. 93, 94 (English).

Individual evidence

  1. ↑ a b c d e f g h i j Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 169
  2. ↑ a b c James E. Eckenwalder: Conifers of the World , p. 145
  3. ↑ a b c d e Liguo Fu, Nan Li, Robert R. Mill: Amentotaxus argotaenia , pp. 93-94 , in Flora of China , Volume 4.
  4. ↑ Armin Jagel: Secretly and often unnoticed: The conifers are in bloom. In: Yearbook of the Bochum Botanical Association. Volume 3, 2012, pp. 227–232 ( PDF 1.6 MB. )
  5. ↑ a b Amentotaxus Argotaenia . Var Argotaenia in the Red List of Threatened Species of the IUCN 2013. Posted by: W. Liao, K. Rushforth, Y. Yang, 2010. Retrieved on January 5, 2014.
  6. ↑ a b Amentotaxus Argotaenia in the endangered Red List species the IUCN 2013 Posted by: C. Hilton-Taylor, Y. Yang, K. Rushforth, W. Liao, 2010. Retrieved on January 3, 2014.
  7. ↑ Podocarpus argotaenia. In: The International Plant Name Index. Retrieved January 3, 2014 .
  8. ↑ Amentotaxus argotaenia. In: The International Plant Name Index. Retrieved January 3, 2014 .
  9. ↑ a b Amentotaxus argotaenia. In: World Checklist of Selected Plant Families. Retrieved January 3, 2016 .
  10. ↑ 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).
  11. ^ A b Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 168
  12. ^ A b Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 170
  13. ↑ Liguo Fu, Nan Li, Robert R. Mill: amentotaxus argotaenia . Var Argotaenia , 93 , in Flora of China , Volume 4.
  14. ^ Liguo Fu, Nan Li, Robert R. Mill: Amentotaxus argotaenia var. Brevifolia , p. 94 , in Flora of China , Volume 4.
  15. ↑ Amentotaxus Argotaenia . Var Argotaenia in the endangered Red List species the IUCN 2013 Posted by: W. Liao, Y. Yang, 2010. Retrieved on January 5, 2014.

Web links

Commons : Amentotaxus argotaenia  - Collection of images, videos and audio files
  • Amentotaxus argotaenia at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed January 3, 2014.
  • Amentotaxus argotaenia in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  • Christopher J. Earle: Amentotaxus argotaenia. In: The Gymnosperm Database. www.conifers.org, November 28, 2012, accessed January 3, 2014 (English).