Walnuts
| Walnuts | ||||||||||||
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Real walnut ( Juglans regia ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Juglans | ||||||||||||
| L. |
The walnuts ( Juglans ) are a genus of plants from the walnut family (Juglandaceae). There are mainly trees, the nut fruits of which are of great economic importance for some species. In Central Europe, the real walnut ( Juglans regia ) is predominantly to be found, while the black walnut ( Juglans nigra ) is much less cultivated or wild .
features
The representatives are deciduous trees or large shrubs. The branches have a chambered Mark . The buds have few bud scales, the terminal bud is enlarged. The side buds are sessile.
The leaves are alternate, unpaired or pinnate in pairs, large, aromatic and without stipules . They consist of 5 to 31 leaflets. The terminal leaflet is rarely reduced. The leaf margin is serrated or entire, the leaf blade is provided with glandular points on the underside.
The plants are monoecious . The male kittens stand individually on their sides on previous year's wood. They stand in the axils of leaf scars, are sessile and drooping. The immature, naked catkins appear in the leaf axils in late summer and overwinter as small, bud-like structures. The female ear consists of 2 to 25 individual flowers and is at the end of this year's shoots. Both male and female flowers are on a bract and have two bracts and four sepals . The number of sepals is often reduced in the male flowers. The bract is small, narrow, not lobed. The male flower has 7 to 85 (rarely up to 105) stamens , which seem to stand on bracts, bracts and sepals, as these are fused with the flower base. The anthers are glabrous, sometimes slightly hairy. The female flowers consist of the bract, two bracts, the free ends of which are lobed, and four sepals. All are equipped with the top of the ovary merged except for their tips. The ovary is thus subordinate. It consists of two carpels, which are arranged median, in individual flowers there are rarely 3 or 4 carpels. The stylus has two elongated, curved stylus branches on the inside of which the scar pads sit.
The fruits ( false fruit ) are large and resemble stone fruits (and are often referred to as such in German-language literature). They consist of a furrowed or wrinkled nut fruit (tryma), which is surrounded by an adherent, thick, fibrous and usually non-opening shell (outer pericarp ). This shell emerges from the bracts and the calyx. The wooden nut wall, the (inner pericarp, endocarp), usually has clear wall cavities. At the base, the nut has two or four compartments. The cotyledons are fleshy, four-lobed and straight. There is a cotyledon in each flap. Germination is hypogean . The knot of the cotyledons has 2 to 4 lacunae and just as many leaf marks.
distribution
The walnuts are the only genus of the family besides Carya that occurs in both the New and the Old World. Its main distribution area is the temperate to subtropical areas of the northern hemisphere. In America, their area extends from southern Canada to northern Argentina. In Asia, it occurs in eastern China, Manchuria, Korea and Japan. The real walnut is the only one found in Europe, its natural area is likely to be the Balkans and the Middle East. Their occurrence from the Caucasus to western China could be caused by humans.
Economical meaning
According to the food and agriculture organization FAO, around 3.8 million t of walnuts (with their shells) were harvested worldwide in 2017 .
The following table gives an overview of the ten largest producers of walnuts worldwide, who produced a total of 92.1% of the harvest.
| rank | country | Quantity (in t ) |
|---|---|---|
| 1 |
 People's Republic of China
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1,925,403 |
| 2 |
 United States
|
571,526 |
| 3 |
 Iran
|
349.192 |
| 4th |
 Turkey
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210,000 |
| 5 |
 Mexico
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147.198 |
| 6th |
 Ukraine
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108,660 |
| 7th |
 Chile
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81.163 |
| 8th |
 Uzbekistan
|
48,397 |
| 9 |
 Romania
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43,720 |
| 10 |
 France
|
40,683 |
| world | 3,829,626 |
Systematics
The genus forms a natural family group, so it is monophyletic . Within the Walnut family and the subfamily Juglandoideae, Juglans, together with Pterocarya and Cyclocarya , whose sister group it is, forms the Subtribus Juglandinae. The generic name Juglans is generalized from the Latin name for the real walnut ; it is on the genitive -Fügung * Di̯ou̯es glans , glans of Jupiter 'recycled, which themselves agr. Διὸς βάλανος DIOS Balanos , chestnut tree (a kind of) Nuss,' seems to be simulated.
Since the work of LA Dode in 1906/1909, the genus Juglans has been divided into four sections . This classification was adopted by most of the other editors of the genus and also confirmed by molecular genetic studies. The subsections of Dode could not be confirmed by molecular genetics.
WE Manning lists 21 species. Sometimes the separation or amalgamation of individual species is discussed differently.
- Section Juglans (also called Dioscaryon )
- Real walnut ( Juglans regia L. )
- Section rhysocaryon
- Juglans australis Griseb. : It occurs in Argentina and Bolivia.
- Juglans boliviana (C. DC.) Dode : It occurs in Bolivia.
- Juglans californica S. Watson : It occurs in California.
- Juglans hindsii (Jeps.) RE Sm.
- Juglans hirsuta W.E. Manning
- Juglans jamaicensis C. DC. : It occurs in Cuba , Hispaniola and Puerto Rico .
- Juglans major (Torr.) A. Heller
- Juglans microcarpa Berland.
- Juglans mollis Engelm. : It occurs in Mexico.
- Juglans neotropica Diels : It occurs in Colombia, Venezuela, Ecuador and Peru.
- Black walnut ( Juglans nigra L. )
- Juglans olanchana Standl. & LO Williams
- Juglans pyriformis Liebm.
- Juglans soratensis W.E. Manning : It occurs in Bolivia.
- Juglans steyermarkii W.E. Manning : It occurs in Guatemala.
- Juglans venezuelensis W.E. Manning : It occurs in Venezuela.
- Cardiocaryon section
- Japanese walnut ( Juglans ailantifolia Carrière )
- Juglans cathayensis Dode : It occurs in the Chinese province of Shandong and in Taiwan .
- Manchurian walnut ( Juglans mandshurica Maxim. )
- Section Trachycaryon Dode ex WE Manning
- Butternut ( Juglans cinerea L. )
The molecular genetic study by Stanford et al. (2000) included 15 of the 21 species and showed the following relationships between the sections:
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supporting documents
- Anmin Lu, Donald E. Stone & LJ Grauke: Juglandaceae , in: Flora of China , Volume 4, 1999, pp. 277-285. Science Press, Beijing and Missouri Botanical Garden Press, St. Louis. (pdf, 153 kB)
- Wayne E. Manning: The Classification within the Juglandaceae . Annals of the Missouri Botanical Garden, Vol. 65, 1978, pp. 1058-1087.
- Alice M. Stanford, Rachel Harden, Clifford R. Parks: Phylogeny and biogeography of Juglans (Juglandaceae) based on matK and ITS sequence data . American Journal of Botany, Volume 87, 2000, pp. 872-882.
Individual evidence
- ↑ a b Alice M. Stanford, Rachel Harden, Clifford R. Parks: Phylogeny and biogeography of Juglans (Juglandaceae) based on matK and ITS sequence data . American Journal of Botany, Volume 87, 2000, pp. 872-882.
- ↑ a b Crops> Walnuts, with shell. In: Official FAO production statistics for 2017. fao.org, accessed on April 9, 2019 .
- ↑ Paul S. Manos, Pamela S. Soltis, Douglas E. Soltis, Steven R. Manchester, Sang-Hun Oh, Charles D. Bell, David L. Dilcher, Donald E. Stone: Phylogeny of Extant and Fossil Juglandaceae Inferred from the Integration of Molecular and Morphological Data Sets . Systematic Biology, Volume 56, 2007, pp. 412-430, doi : 10.1080 / 10635150701408523
- ^ Heinrich Marzell , Heinz Paul: Dictionary of German Plant Names II, Leipzig 1972 (Cologne 2000, reprint), p. 1053.
- ^ Wilhelm Pape , Concise Dictionary of the Greek Language. Greek-German concise dictionary , vol. 1: Α – Κ, edited by Maximilian Sengebusch , 3rd edition, 6th copy, Braunschweig 1914, p. 428 sv βάλανος .
- ↑ a b c d e f g h i j Juglans in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved December 30, 2016.
