Torreya

Florida Nutmeg ( Torreya taxifolia )

The nut yew ( Torreya ) constitute a genus of flowering plants in the family of Yews ( Taxaceae ). Today it has a disjoint area with species in the southeastern and western United States and in China and Japan.

• 4.1 Notes and references

Description

Vegetative characteristics

Nut yew species are evergreen shrubs or small trees. The branches are arranged in whorls and branches against almost constantly until almost whorled. The bark is brown to grayish - brown. The needles appear to be arranged in two rows on the branch. The winter buds have some decussate arranged pairs of bud scales. The seedling has only two seed leaves ( cotyledons ).

The leaves are decussate or placed almost against constantly and double-spaced on the branches. Filmed at their base leaves are leathery and linear or linear- lanceolate with down -going basis and sharply tapered at the top. On the slightly convex leaf underside two Stomatabänder and resin canals are present and the median nerve is more or less vaguely recognizable.

Generative features

They are usually dioecious getrenntgeschlechtig ( dioecious ), very rarely monoecious ( monoecious ).

The male cones are individually and laterally also a short shaft. The male cones are ellipsoid or short columnar and contain six to eight whorls with four Mikrosporophylle. Each microsporophyll rarely has three or four usually hanging pollen sacs ( microsporangia ).

The female cones are arranged in pairs sitting in the leaf axils. The female cones have two pairs cross against constant cone scales and a lateral. It's just an upright seed conditioning. There is a succulent aril at the base of durable cone scales. This green seed coat ( aril ) surrounding the seeds; both structures interact drupe -like. The seeds need from fertilization to maturity in the fall about two years.

The chromosome numbers be 2n = 22

Dissemination

The genus Torreya now has a disjoint area with species that occur only in North America ( in the southeastern and western U.S.) or only Asia ( China and Japan). The Torreya species occur today mainly on the Pacific coasts and their distribution indicates a formerly continuous distribution zone across the Bering Strait.

They thrive in isolated forests.

System

The genus Torreya was erected in 1838 by George Arnott Walker Arnott in the Annals of Natural History, 1, pp. 130-132. There are also other publications for this genus name, but Arnott was determined as the valid one. The botanical genus name Torreya honors the botanist John Torrey U.S. ( 1796-1873 ). A synonym for Torreya Arn. is Tumion Raf ..

There are six in the genus Torreya species, which are given here with their area of ​​distribution:

• California Nutmeg ( Torreya californica Torr. ): It occurs only in California.
• Torreya fargesii Franchet: It grows in forests at altitudes 1000-3400 meters in the Chinese provinces: western Hubei, northwestern Hunan, Jiangxi, southern Shaanxi, Sichuan, northwestern Yunnan, and perhaps in southern Anhui.
• Large Nutmeg ( Torreya grandis Fort ): It grows on hills, open valleys, often along watercourses to " yellow, red and dark floors " at altitude 200-1400 meters in the Chinese provinces: southern Anhui, northern Fujian, northeastern Guizhou, western Hunan, southern Jiangsu, northern Jiangxi and Zhejiang.
• Torreya jackii Chun: It grows in forests at elevations between 400 and 1000 meters in the Chinese provinces: northern Fujian, northeastern Jiangxi and southern Zhejiang.
• Japanese Nutmeg ( Torreya nucifera Sieb & Zucc. . ), Also called Japanese Stinkeibe: You naturally occurs only in Japan. It is used as an ornamental plant.
• Eibenblättrige Nutmeg ( Torreya taxifolia Arn. ): It is native only in Georgia ( just in Decatur County) and Florida (only in Gadsden, Jackson and Liberty County).

Swell

• Christopher J. Earle: Torreya. In: The Gymnosperm Database. December 12, 2010, accessed 30 October 2011 (HTML, English).
• Liguo Fu, Nan Li, Robert R. Mill: Taxaceae: Torreya. 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, page 94.
• Jianhua Li, Charles C. Davis, Michael J. Donoghue, Susan Kelley, Peter Del Tredici: Phylogenetic relationships of Torreya ( Taxaceae ) inferred from sequences of nuclear ribosomal DNA its region. In: Harvard Papers in Botany. Volume 6, 2001, pp. 275-281. Full-text PDF.
• Walter Erhardt et al: The big walleye. Encyclopedia of plant names. Volume 2 Eugen Ulmer Verlag, Stuttgart, 2008. ISBN 978-3-8001-5406-7