Emex

Stechampfer ( Emex spinosa)

Stechampfer ( Emex ) is a plant genus of the family of the buckwheat family ( Polygonaceae ). The genus contains only two species, both of which are invasive plants and dreaded weeds.

• 4.1 Notes and references

Description

Appearance and leaves

Stechampfer species are annual herbaceous plants out form a taproot. The plant parts are bare, the stems decumbent to erect.

The alternate on the stem arranged leaves are seasonal green and stalked. The Ochrea is membranous to papery and often drops out. The simple leaf blade is almost spit -shaped, triangular, ovate or ovate - oblong. The leaf margin is smooth to obscurely crenate or dentate, sometimes wavy.

Inflorescences and flowers

The Stechampfer species are monoecious getrenntgeschlechtig ( monoecious ). You can bloom all year. The grape -like inflorescences are terminal or axillary and stalked. The unisexual flowers are on separate inflorescences on a copy. The male flowers are stalked, the female flowers have no or almost no stalk. The perianth consists of rare five or six usually greenish, sepal -like bloom cladding that have grown in the male flowers freely, and when the female flowers at its base, bell-shaped, and, especially with the female flowers have two different forms. About a Ochrea is a bundle of one to eight male flowers. The male flowers contain four to six free stamens with yellowish to reddish, elliptic to ovate anthers. About a Ochrea is a bundle of one to seven female flowers. The female flowers contain three upright style.

Fruit and seeds

Surrounded by the tough, hardened and verdornten perianth achenes are glabrous, brown, triangular (not a triptych ) and shiny. The seeds contain a curved embryo.

Chromosome numbers

The basic chromosome number is x = 10

Dissemination

The original distribution area of ​​Stechampfers ( Emex spinosa) is located in the Mediterranean and the Orient. Emex australis is native to Southern Africa: Namibia, Swaziland, Lesotho and South African provinces of Cape Province, Free State, KwaZulu -Natal and the Transvaal; australis means "south ", but not " Australia ", hence the common name would be "Southern Stechampfer " right.

Both plant species have spread invasive throughout the tropical, subtropical and temperate area of the earth. They displace other plant species and cause serious damage in agriculture, so they are considered " agricultural pest " ( "agricultural pest" ).

System

Noel Martin Joseph de Necker published in 1790 the generic name Emex in his work Elementa botanica and incorporated it in the genus Rumex off ( deriving from Emex " Ex" Rumex ). This publication is not valid because this book is one of the oppressed by ICBN works. The name Emex only became valid in 1819 by the publication of Francisco Campderá. He had actually against the legitimate priority synonym Vibo Medik. be preserved, which was published in 1789.

The only style set Campderá Emex spinosa in the genus and put in contrast to the masculine gender of the generic name Rumex on feminine fixed. The sometimes -to-find orthographic variant " Emex spinosus " is not regularly meet for that reason. In 1838 Adolph Steinheil described a second type, Emex australis .. Both Emex species also form hybrids that have been reported for the first time in 1980.

The genus belongs to the tribe Emex Rumiceae in the subfamily within the family Polygonaceae Polygonoideae. It contains only two types:

• Stechampfer ( Emex spinosa (L.) Campd. )
• Emex australis Steinh.

Swell

• Craig C. Freeman: Emex. In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico. Volume 5: Magnoliophyta: Caryophyllidae, part 2, Oxford University Press, New York / Oxford et al 2005, ISBN 0-19-522211-3, pp. 487-488 ( limited preview on Google Book Search ). (Sections Description and systematics).
• Mohammad Qaiser: Flora of Pakistan 205: Polygonaceae. University of Karachi, Department of Botany / Missouri Botanical Press, Karachi / St. Louis in 2001, online ( section description).