Thorn elm

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Thorn elm
Hemiptelea-davidii-habit.jpg

Thorn Elm ( Hemiptelea davidii )

Systematics
Rosids
Eurosiden I
Order : Rose-like (rosales)
Family : Elm family (Ulmaceae)
Genre : Hemiptelea
Type : Thorn elm
Scientific name of the  genus
Hemiptelea
Planch
Scientific name of the  species
Hemiptelea davidii
( Hance ) Planch

The Dornulme ( Hemiptelea davidii ) is the only kind of monotypic genus Hemiptelea within the family of the Elm Family (Ulmaceae). It comes from China and Korea and is often used there for planting hedges or as an ornamental wood. The German common name Dornulme refers to the short shoots transformed into thorns .

description

bark
Branch with simple, serrated leaves and maturing wing nuts

Appearance and leaf

The thorn elm grows as a deciduous, small tree with a spreading growth or shrub . In its homeland it reaches heights of growth of 10, rarely up to 12 meters. The bark is dark gray to grayish brown. The often rigid twigs have a grayish-brown to brownish-purple, initially fluffy bark and 2 to 10 centimeters long, short shoots that have been transformed into strong thorns . The egg-shaped winter buds usually grow in threes in the leaf axils.

The alternate and two lines are arranged on the branches leaves are divided into petiole and leaf blade. The downy hairy petiole is relatively short with a length of 3 to 5 millimeters. The simple leaf blade is at a length of 4 to 7 centimeters and a width of 1.5 to 3 centimeters elliptical to elliptical-elongated or rarely obovate-elliptical with a pointed or rounded to blunt upper end. The base of the blades is rounded to more or less heart-shaped, but not crooked as is often the case with other species of the Ulmaceae family. The leaf margin is roughly serrated with blunt teeth. The upper side of the leaf is dark green and sparsely hairy, the underside is lighter and only sparsely hairy on the leaf veins. There is pinnate veins with eight to twelve leaf veins on each side of the central vein, which extend to the leaf margin and each end in the leaf teeth. The two membranous, elongated to lanceolate stipules with a length of 3 to 4 millimeters leave short transverse leaf scars on each side of the leaf base when they fall off.

Flower and fruit

In China, the spring bloom extends from April to May and the flowers appear at the same time as the leaves. In Hemiptelea davidii is polygamy before, but the flowers are often hermaphroditic. The stalked flowers are single or in clusters of two to four in the leaf axils of the young branches. The relatively small flowers are four or five-fold. The four or five bracts are fused cup-shaped. The four or five fertile stamens are free from each other, but fused with the base of the bracts. The two carpels are an upper continuous, single-chamber, laterally flattened ovary deformed, only a ovule contains. The short style ends in two linear scar branches.

The flower cover is still present on the relatively small nut fruit and it is winged on one side, i.e. a wing nut. The asymmetrical, crooked nut fruit is flattened on both sides and ovoid with a length of 5 to 7 millimeters. The narrow wing is comb-shaped. The 2 to 4 millimeters long and slender stalked seed is elongated and curved. The upright embryo has two broad germ layers ( cotyledons ). The nut fruit ripens in China from September to October and is then yellowish-green.

Chromosome set

The number of chromosomes is 2n = 56.

Occurrence

Hemiptelea davidii is common in Korea and the Chinese provinces of Anhui , Gansu , northern Guangxi , Hebei , Heilongjiang , Henan , Hubei , Hunan , Jiangsu , Jiangxi , Jilin , Liaoning , Nei Mongol , Ningxia , Shaanxi , Shandong , Shanxi and Zhejiang . It grows in China at altitudes below 2000 meters on mountain slopes, roadsides and is planted around houses.

Systematics

The first description was in 1868 under the name ( Basionym ) Planera davidii by Henry Fletcher Hance in Journal of Botany, British and Foreign , Volume 6, 71, p. 333. The genus Hemiptelea was in 1872 by Jules Émile Planchon in Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences , 74, p. 131 with the type species Hemiptelea davidii (Hance) Planch set up. Other synonyms for Hemiptelea davidii (Hance) Planch. are: Zelkova davidiana Franch. ex Mottet , Hemiptelea davidiana Priemer , Zelkova davidii (Hance) Hemsl. , Zelkova davidiana (Priemer) Bean .

Hemiptelea davidii is the only species of the monotypic genus Hemiptelea within the Ulmaceae family .

use

Hemiptelea davidii is used as an ornamental plant.

Devices are made from the hard wood . The fibers from the bark are used to manufacture bags, for example. Drinks are made from the delicate leaves. An oil is extracted from the seeds.

literature

Individual evidence

  1. ↑ a b c d e f g h i j Allen J. Coombes: Leaves and their trees: 600 portraits. Haupt Verlag, Bern / Stuttgart / Vienna 2012, ISBN 978-3-258-07738-3 , p. 623.
  2. ↑ a b c d e f g h i j k l m n o p q r s t u v w x Liguo Fu, Yiqun Xin & Alan Whittemore: Ulmaceae. : Genus Hemiptelea and species Hemiptelea davidii , p. 9 - online with the same text as the printed work In: Wu Zhengyi, Peter H. Raven, Deyuan Hong (Ed.): Flora of China. Volume 5: Ulmaceae through Basellaceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, December 19, 2003, ISBN 1-930723-27-X .
  3. ↑ a b c d Hemiptelea in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 16, 2014.
  4. ↑ Hanes scanned in at biodiversitylibrary.org in 1868 .
  5. ^ Planchon scanned in 1872 at biodiversitylibrary.org .
  6. ↑ a b Hemiptelea at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed June 16, 2014.

Web links

Commons : Thorn Elm ( Hemiptelea_davidii )  - Album with pictures, videos and audio files