Shore pointed burdock
| Shore pointed burdock | ||||||||||||
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Elbe cocklebur ( Xanthium albinum subsp. Albinum ) |
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| Scientific name | ||||||||||||
| Xanthium albinum | ||||||||||||
| ( Aries ) H.Scholz |
The Shore cocklebur ( Xanthium albinum ) is a plant from the genus of cocklebur ( Xanthium ) that the family of the daisy family belongs (Asteraceae). It is a new species in Europe that emerged from naturalized xanthium species from North America.
description
Vegetative characteristics
The riverside burdock grows as an annual herbaceous plant and reaches heights of a maximum of 100 centimeters. The vegetative parts of the plant are yellow-green, often overflowing with red on the stem , smell aromatic and are relatively coarse hairy. The alternate leaves are broadly triangular to heart-shaped (with the subspecies Xanthium albinum subsp. Riparium also with a wedge-shaped base).
Generative characteristics
The flowering period extends from August to October. The small, yellow male flower heads are flattened at the base and fall off early. The larger, green female flower heads and later fruit clusters have straight beaks, curved only at the tip, as well as dense covering spines, some of which are pointed like a needle, others curved like a crochet needle. They use the burdock effect by getting caught on the fur of animals passing by or on floating debris and thus spreading them out. While the subspecies Xanthium albinum subsp. albinum, which when ripe are brownish, thickly ovate (2.5 times as long as they are wide), they are found in the subspecies Xanthium albinum subsp. riparium slim ellipsoid (3.5 times as long as wide).
Chromosome number
The number of chromosomes is 2n = 36.
Occurrence
The riparian burdock is a typical river valley plant that occurs almost exclusively on alternately wet bank fringes and in therophyte beds along larger rivers in Europe, e.g. B. widespread on the Elbe , the Havel , the Spree and the Oder , rarely also on the Weser , Rhine and Moselle . The subspecies albinum (Elbe pointed burdock) is even endemic to Central Europe, with a special focus on the middle and lower Elbe. Of about five xanthium species occurring in Central Europe , only the common pointed burdock ( Xanthium strumarium ) is considered to be possibly indigenous ; the others are seen as naturalized neophytes originating from North America or - in the case of the lace burdock - as newly created species based on naturalized plants. The systematics of pointed burdock in Europe has not yet been conclusively clarified. The pointed burdock is often found in the weed edges of the river banks on open, wet, nutrient-rich, humus-rich, mild, mostly sandy, also gravelly or pure clay soils. It is a character species of the Xanthio-Chenopodietum from the association Chenopodion rubri.
The pointed burdock should not with the genus of burdock ( Arctium ), z. B. Great burdock , Arctium lappa , may be confused.
Systematics
A distinction is made between the subspecies:
- Elbe cocklebur ( Xanthium albinum subsp. Albinum )
- Eastern or slender-headed pointed burdock ( Xanthium albinum subsp. Riparium (Čelak.) Widder & Wagenitz ; syn .: Xanthium italicum subsp. Riparium Čelak. ).
literature
- Henning Haeupler , Thomas Muer: picture atlas of the fern and flowering plants of Germany (= the fern and flowering plants of Germany. Volume 2). Published by the Federal Agency for Nature Conservation. Ulmer, Stuttgart 2000, ISBN 3-8001-3364-4 .
Individual evidence
- ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp. 925 .
Web links
- Elbe pointed burdock. In: FloraWeb.de.
- Eastern shore pointed burdock. In: FloraWeb.de.