Torreya fargesii

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Torreya fargesii
Systematics
Subdivision : Seed plants (Spermatophytina)
Class : Coniferopsida
Order : Conifers (Coniferales)
Family : Yew family (Taxaceae)
Genre : Nut slices ( Torreya )
Type : Torreya fargesii
Scientific name
Torreya fargesii
Franch.

Torreya fargesii is a shrub or tree-like conifer from the genus of the nut slices ( Torreya ). The natural range is in China. The species is classified as endangered inthe IUCN Red List .

description

Appearance

Torreya fargesii grows as an evergreen shrub or tree up to 20 meters high . The trunk reaches diameters of up to 1 meter at chest height . The trunk bark is pale brown to gray-brown and dark gray and irregularly vertically cracked when exposed to the weather. Sometimes it flakes off. The branches grow spread out and ascending and form a broad treetop. Leafy branches are thin and terete. Young shoots are green in the first year and then yellowish brown.

Buds and needles

The vegetative buds on the ends of the branches are very small. The bud scales of the annual nodes are enlarged, broadly triangular, keeled and shiny brown. They fall off soon after the first year. The needles are arranged in a comb shape, go from the branches at an angle of 55 ° to 90 ° and grow on a 0.5 to 1 millimeter long, twisted stem. They are linear to linear-lanceolate, straight or curved sickle-shaped towards the tip, 1.2 to 3.5 and rarely up to 4.5 centimeters long and 2 to 4 millimeters wide. They suddenly widen towards the base and merge conically into a sharply pointed end. The needles are leathery and shiny green on top with two grooves that run along the indistinct midrib at least in the lower half of the needle. On the underside of the needle there are two light brown, 0.3 to 0.5 millimeter wide stomata opening bands , separated from each other by the 0.3 to 0.6 millimeter wide, green central rib and from the needle edge by 0.5 to 1.2 millimeter wide green stripes are separated. The edge of the needle is straight or curled up very tightly. Unlike other nut slices, the needles do not give off an aromatic fragrance when rubbed.

Cones and seeds

The pollen cones grow individually in the needle axles and form short rows on the underside of sideways branches. At the base of the cones there are four to twelve pairs of bud scales in rows of four. The cones are pale yellow and about 5 to 6 millimeters long with a diameter of 4.5 to 5 millimeters when the pollen is released. The numerous microsporophylls are shield-shaped and sometimes only carry three, usually four or five, hanging, small pollen sacs.

The structures containing the seed grow in pairs, sometimes grouped in multiple pairs on a branch. They are seated with rounded and keeled deck scales. The ripe aril is fleshy, smooth, pale green or slightly whitish, egg-shaped, rounded or broadly elliptical, with a diameter of 15 to 25 millimeters and prickly. The actual seed is smooth or has two opposite ridges.

The pollen is released in April and May, the seeds ripen after two years in September and October.

Distribution and ecology

The natural range of Torreya fargesii is in China in the city of Chongqing , possibly in the south of Anhui , in the west of Hubei , in the north-west of Hunan , in Jiangxi , in the south of Shaanxi , in Sichuan on the Emei Shan and in the north-west of Yunnan . Torreya fargesii grows individually or in groups along rivers or on mountain slopes at heights of 1000 to 3400 meters in coniferous forests, mixed forests or deciduous forests, bush-shaped as undergrowth or as a small to medium-sized tree. The distribution area is assigned to winter hardiness zone 7 with mean annual minimum temperatures between −17.7 and −12.3 ° Celsius (0 to 10 ° Fahrenheit ).

Hazard and protection

In the Red List of the IUCN is Torreya fargesii as endangered ( "Vulnerable") out. Stocks have decreased by 30 to 40 percent over the past 150 years, with the largest decrease occurring in recent years. The greatest danger is further deforestation in the distribution area.

Systematics and Etymology

Torreya fargesii is a species from the genus of the nut slices ( Torreya ). It was first described in 1899 by Adrien René Franchet as Torreya fargesii . In 1984 John Silba introduced it as a variety Torreya grandis var. Fargesii (Franch.) Silba to the species Torreya grandis , but the taxon is in the Flora of China, by James E. Eckenwalder in Conifers of the World and by Aljos Farjon in A Handbook of the World's Conifers continue to be classified as a separate species. It differs from Torreya grandis in the width of the stomata bands on the underside of the needle. The separating central rib is narrower in Torreya fargesii than the green stripes on the edges, which are about the same size in Torreya grandis . This means that the stomata bands in Torreya fargesii are wider than those of Torreya grandis , as the needle width of the two species is roughly the same. Despite the similarity to Torreya grandis , genetic studies show a closer relationship to the Japanese species Torreya nucifera , which can be distinguished from the two species by the aromatic smell when the needles are rubbed and the reddish brown three-year-old branches.

The generic name Torreya is reminiscent of the American botanist and chemist John Torrey (1796–1873), who wrote the two-volume work A Flora of North America together with Asa Gray . The specific epithet fargesii honors the French missionary and plant collector Paul G. Farges (1844–1912), who also found the type specimen in Sichuan.

There are two varieties:

  • Torreya fargesii var. Fargesii : The needles are straight or rarely curved towards the tip in a sickle shape, 1.5 to 2.5 centimeters long and 2 to 3.5 millimeters wide. The end of the needle only converges over a short area towards the point. The grooves on the top of the needle usually only reach the middle of the needle and disappear towards the tip. The green stripes on the edge of the needle are 0.5 to 0.9, rarely up to 1.1 millimeters wide. The range is in Chongqing, possibly in the south of Anhui, in the west of Hubei, in the northwest of Hunan, in Jiangxi, in the south of Shaanxi and in Sichuan. There it grows in coniferous and deciduous forests at altitudes of 1000 to 1800 meters. The variety is listed by the IUCN as endangered ("Endangered"). The wood is in great demand and the stocks have now shrunk to young, small trees in inaccessible areas. Together there are still around 53,000 specimens with only a few seedlings and old trees. The holdings were probably much more extensive in the past, but were heavily overexploited. Stocks are believed to have decreased by over 50 percent over the past 150 years and the decline will continue. At lower altitudes, the variety is also endangered by the clearing of forests to provide arable land. Felling trees is now prohibited (as of 2013), but the ban is difficult to enforce. However, some stocks are located in protected areas.
  • Torreya fargesii var. Yunnanensis (WCCheng & LKFu) N.Kang : The needles are straight or often curved sickle-shaped towards the tip, but from 1.5 usually 2 to 4 centimeters long and 3 to 4.5 millimeters wide. The grooves on the top of the needle reach (almost) the point. The needles converge from about the middle towards the tip. The green stripes on the edge of the needle are usually 0.9 to 1.2 millimeters wide from 0.7. The natural range is in the northwest of Yunnan in Gongshan , Lijiang , Weixi and in Shangri-La . There it often grows locally in coniferous and mixed forests in a warm, temperate climate at altitudes of 1500 to 3400 meters. The variety yunnanensis is also listed as endangered by the IUCN. The area of ​​distribution ("extent of occurrence") has a size of only about 3580 square kilometers, there are about ten populations on a total of about 384 square kilometers ("area of ​​occupancy"). There are still around 8 million trees in total, but very few large, fully grown specimens. Despite a ban, full-grown trees are still felled because the wood is in great demand. Humans also degrade the quality of the tree's habitat and the population continues to decline. Some of the stocks grow in protected areas.

use

The wood from Torreya fargesii is of high quality and very resistant to moisture and contact with earth. It is therefore used for building houses and bridges, and for making furniture. The trees are also suitable for afforestation. The seeds are edible and oil is made from them. The essential “Torreya oil” is only produced from the aril. The species is cultivated in China, but is less common than Toreya grandis . Outside of China, they are only found in a few botanical gardens and arboretums .

swell

literature

  • Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 978-90-04-17718-5 , pp. 998-1001 .
  • James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 615-616 .
  • 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. 95 (English).
  • Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 649 (reprint from 1996).

Individual evidence

  1. ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, pp. 999-1000
  2. ↑ a b c d e f g h i Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 1000
  3. ↑ a b c James E. Eckenwalder: Conifers of the World , p. 615
  4. ↑ a b c d e Liguo Fu, Nan Li, Robert R. Mill: Torreya fargesii , in Flora of China , Volume 4, p. 95
  5. ↑ Torreya fargesii in the endangered Red List species the IUCN 2013. Posted by: Y. Yang, D. Luscombe, 2010. Accessed December 25, 2013.
  6. ↑ a b c Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 999
  7. ↑ Torreya fargesii. In: The Plant List. Retrieved December 27, 2013 .
  8. ↑ a b James E. Eckenwalder: Conifers of the World , p. 616
  9. ↑ Exactly: Etymological Dictionary of Botanical Plant Names , p. 649
  10. ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 998
  11. ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, pp. 1000-1001
  12. ^ Liguo Fu, Nan Li, Robert R. Mill: Torreya fargesii var.fergesii , in Flora of China , Volume 4, p. 95
  13. ↑ Torreya fargesii var. Fargesii in the endangered Red List species the IUCN 2013 Posted by: C. Hilton-Taylor, Y. Yang, D. Luscombe, 2010. Accessed December 27, 2013.
  14. ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 1001
  15. ^ Liguo Fu, Nan Li, Robert R. Mill: Torreya fargesii var.yunnanensis , in Flora of China , Volume 4, p. 95
  16. ↑ Torreya fargesii var. Yunnanensis in the endangered Red List species the IUCN 2013. Posted by: Y. Yang, D. Luscombe, 2010. Accessed December 27, 2013.

Web links

  • Torreya fargesii at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed December 27, 2013.
  • Torreya fargesii in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  • Christopher J. Earle: Torreya fargesii. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed December 27, 2013 .