Himalayan knotweed
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Northern knotweed ( Aconogonon polystachyum ) |
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| Aconogonon polystachyum | ||||||||||||
| ( Wall. Ex Meisn. ) Small |
The Himalaya knotweed (also: Himalaya mountain knotweed, Himalaya knotweed, polygonaceae) is a species of plant from the knotweed family (Polygonaceae) native to the Himalayas and neighboring mountain ranges of East Asia. The species was cultivated as an ornamental plant, was introduced as a neophyte to Europe and North America, where it is established growing wild.
features
Himalayan knotweed is an upright, richly branched perennial shrub whose shoots sometimes at the base woody . The shoots usually arise in several groups from a perennial rootstock, which allows dense herds or thickets to develop. Its height is very variable, heights of 30 centimeters to 2.5 meters, usually one, more rarely up to two meters, are given in various floristic plants. The shoots arise from underground soil shoots ( rhizomes ). The stem axis is upright and richly branched, it is lightly hairy to bald and usually brownish in color, it is usually somewhat angular. As is typical for the family, the leaves have a brown to reddish-brownish sheath , called Ochrea , around the adjacent stem section ( internode ) of one to four centimeters in length. The leaves are usually clearly short stalked or almost sessile. The leaf blade is variable in size, usually about 5 to 20, rarely up to 30 centimeters long and 3 to 7 centimeters wide, it is lanceolate and pointed at the end. The base of the spreiten is straight to heart-shaped. It is lightly hairy to almost bald on the upper side or only hairy on the leaf veins, on the underside usually densely pubescent tomentose hair.
The inflorescence is a terminal, richly branched, paniculate thyrse . The individual flowers are white to pink or reddish in color and 3 to 5 millimeters long. The inflorescence usually consists of five tepals , which are designed somewhat unevenly; the outer three are larger than the inner two. They are oblong to obovate. They are free to the base and not grown together. When the fruit is ripe, they are neither blackened nor enlarged. The eight stamens have reddish colored anthers. The ovary is triangular with three free styluses with a heady stigma. The brownish, approx. 2.5 millimeters long fruit is enclosed in the permanent flower cover.
The species is flowering late in the year, in its homeland from June to September, in Central Europe usually only from September to October. The flowers have an intense scent of vanilla.
The chromosome number is 2n = 22.
distribution
The natural range of the species is in the Himalayas in India, Pakistan, Afghanistan, Bhutan, Sikkim and Nepal, as well as in China and in the north of Myanmar. In China it is given for the west of the country, in Sichuan , Yunnan and in the Tibet Autonomous Region . In Europe it was given, initially adventively , for north-western Europe and Switzerland. It is now naturalized throughout Switzerland. In Germany, only a few naturalized occurrences in the south-western low mountain ranges, in the Black Forest and in the Allgäu, are firmly established, but occasionally they occur overgrown from culture far beyond, these occurrences are currently not considered to be established. In Poland, only one deposit, in the Niepołcko Castle Park, is considered to be firmly established. In England, the species has so far mainly appeared subspontaneously in places where garden waste is deposited, but its establishment is considered likely.
Location
The species grows in its home in the mountains, it is given in China at altitudes between 2200 and 4500 meters, in Pakistan from 1500 to 3000 meters. Neophytic populations also occur deeper in northern latitudes, in Alaska to sea level. The species prefers relatively cool, mostly humid locations in Europe. It is found on the banks of water, on the edges of forests and roads, and on embankments, where it often grows in pure stands with few species. Like other invasive knotweed species, the species reproduces mainly vegetatively in Europe via the rhizomes; it often does not reach seed maturity.
The species is soil-vague and can colonize soils from acidic to neutral areas (around pH 7). It prefers clearly nutrient-rich soils. It is only moderately shade tolerant.
use
The Himalayan knotweed is occasionally used phytomedically in its region of origin . The herb is used, for example, for digestive problems.
The species is still occasionally offered in the garden trade as an ornamental plant. Because of the danger as an invasive neophyte, their use is not recommended.
natural reserve
The species is considered an invasive neophyte in Switzerland and as such was included in the list of the Ordinance on Handling Organisms in the Environment (Release Ordinance). This means that handling the plant (with the exception of controlling it) and trading it as an ornamental plant is prohibited in Switzerland.
Taxonomy and systematics
The species was first described as Polygonum polystachyum in 1832. There is no agreement about their genre. In addition to being assigned to the genus Aconogonon (also spelled Aconogonum ), other taxonomists also list it in the genera Persicaria , Rubrivena and Koenigia . When assigned to the genus Persicaria , many authors preferred the name Persicaria wallichii Greuter & Burdet, as there is the homonym Persicaria polystachya Opiz for the combination Persicaria polystachya (Wall. Ex Meisn.) H.Gross .
The genus Aconogonon was founded in 1826 by Karl Friedrich Meißner as Polygonum sect. Aconogonon introduced and raised to an independent genus by Ludwig Reichenbach in 1837 . The affiliation of the Himalayan knotweed was mainly based on the loose, paniculate inflorescence and the obliquely cut ochrea, which, however , was introduced as Persicaria sect with the genus Rubrivena . Rubrivena , has in common.
Therefore, based on morphological characteristics, no agreement could be reached on the division of the tribe Persicariae into species. Phylogenomic studies, based on the comparison of homologous DNA sequences, suggested a classification in a separate genus Rubrivena , which would be the sister group of Koenigia and Aconogonon . According to a more recent analysis, a position relatively basal to the species listed in Aconogonon appears more likely; however, according to the results, the recognition of the genus Aconogonon , even in a broad definition, would make the genus Koenigia paraphyletic . The authors therefore propose to include all species in a broad genus Koenigia , the species would then have to be Koenigia polystachya (Wall. Ex Meisn.) TMSchust. & Reveal are called. However, this result has not yet been included in directories or florists.
In the German standard list of fern and flowering plants (as of October 2018) it is listed as Aconogonon polystachyum .
Individual evidence
- ↑ a b Polygonum polystachyum in Li Anjen, Bao Bojian, Alisa E. Grabovskaya-Borodina, Suk-pyo Hong, John McNeill, Sergei L. Mosyakin, Hideaki Ohba, Chong-wook Park (2003): Polygonaceae. Flora of China 5: 277-350.
- ↑ a b Rubrivena polystachya in M. Qaiser: Polygonaceae. Flora of Pakistan 205.
- ↑ a b Persicaria wallichii in Craig C. Freeman & James E. Reveal: Polygonaceae, in Flora of North America vol. 5: Magnoliophyta: Caryophyllidae, part 2. Oxford University Press, 1993. ISBN 978-0-19-522211-1 , at page 581.
- ↑ a b c Alaska Natural Heritage Program: Himalayan knotweed, Persicaria wallichii, Fact Sheet. Alaska Center for Conservation Science, University of Alaska. download
- ^ Eckehart J. Jäger, Friedrich Ebel, Peter Hanelt, Gerd K.Müller: Rothmaler excursion flora from Germany. Volume 5: Herbaceous ornamental and useful plants. Spectrum Akademischer Verlag (Springer), Berlin / Heidelberg 2008. ISBN 978-3-8274-0918-8 , on page 210.
- ↑ a b Dietmar Brandes (1989): Reference to the naturalization of Polygonum polystachyum Wall. Ex Meisn .. Floristic Circulars 23 (1): 50-51.
- ↑ a b c Himalayan knotweed, Polygonum polystachyum. Invasive Neophytes: Threat to Nature, Health, and Economy, Blacklisted Type. www.infoflora.ch PDF, 2012
- ↑ Himalayan knotweed, Aconogonon polystachyum . FloraWeb - data and information on wild plants and vegetation in Germany, published by the BfN Federal Agency for Nature Conservation, with distribution map. Data status October 2013.
- ↑ Wanda Bacieczko, Agnieszka Borcz, Emilia Kaszycka (2015): Ecological characteristics of Polygonum polystachyum population in north-western Poland (West Pomerania: Niepołcko). Polish Journal of Natural Sciences 30 (1): 35-46.
- ↑ Himalayan knotweed (Persicaria wallichii). Rapid Risk Assessment Summary Sheet , updated September 2015. NNSS GB non-native species secretariat.
- ↑ Hao Da, Xiao Jie Gu, Pei Gen Xiao: Medicinal Plants: Chemistry, Biology and Omics. Woodhead Publishing, 2015. ISBN 978-0-08-100103-5 , at page 483.
- ↑ Umberto Quattrocchi: CRC World Dictionary of Medicinal and Poisonous Plants: Common Names, Scientific Names, Eponyms, Synonyms, and Etymology. CRC Press, 2016. ISBN 978-1-4822-5064-0 , on page 3035.
- ↑ Knöterich, Perennial of the Year 2012 (PDF) leaflet, Association of German Perennial Gardeners.
- ^ Gabriele Galasso, Enrico Banfi, Fabrizio De Mattia, Fabrizio Grassi, Sergio Sgorbati, Massimo Labra (2009): Molecular phylogeny of Polygonum L. s. l. (Polygonoideae, Polygonaceae), focusing on European taxa: preliminary results and systematic considerations based on rbcL plastidial sequence data. Atti della Società italiana di scienze naturali e del Museo civico di storia naturale di Milano 150 (1): 113-148.
- ^ Adriana Sanchez, Tanja M. Schuster, Janelle M. Burke, Kathleen A. Kron (2011): Taxonomy of Polygonoideae (Polygonaceae): A new tribal classification. Taxon 60 (1): 151-160. JSTOR 41059829
- ↑ Tanja M. Schuster, James L. Reveal, Michael J. Bayly, Kathleen A. Kron (2015): An updated molecular phylogeny of Polygonoideae (Polygonaceae): Relationships of Oxygonum, Pteroxygonum, and Rumex, and a new circumscription of Koenigia. Taxon 64 (6): 1188-1208. doi: 10.12705 / 646.5
- ↑ Aconogonon polystachyum in lists of vascular plants in Germany, standard list of fern and flowering plants in Germany. EDIT European Distributed Institute of Taxonomy, accessed October 17, 2018.
