Ragweed (Ambrosia)
Family:
Daisy family (Asteraceae)
Flowering period:
August-September
Distribution:
mainly native to North America, introduced from there to Europe, Asia and Australia, invasive, is spread by humans through contaminated bird food and construction equipment, spreads particularly in ruderal habitats and disturbed soils (roadsides, gravel pits, rubbish dumps and construction sites)
Appearance:
annual to perennial herbaceous plants, leaves are alternate or opposite, petiolate or sessile, the leaf blade is simple to pinnate to the leaf edges are smooth to serrated, in contrast to mugwort the lower leaf surface is green, the cup shaped male flowers are borne in terminal candle-like inflorescences, females appear in leaf axes underneath, hairy stems
Important species in Europe:
Ambrosia artemisiifolia (common ragweed): can grow up to 1.8 m high in Central Europe, annual
Ambrosia trifida (giant ragweed): three pinnate leaves (grows up to 4m high)
Ambrosia psilostachya (Perennial ragweed): predominantly spread through their roots, thus produces fewer seeds than A. artemisiifolia
Allergenicity:
responsible for "fall hay fever", highly allergenic, a few pollen grains per m3 of air are sufficient to cause irritation, often leads to asthma as well as skin symptoms (dermatitis), cross-reactions with goldenrod, sunflower, chamomile, Arnica and other Asteraceae are possible, Amb a1 is the main allergen
Link zum Pollenatlas: Ambrosia artemisiifolia
Wissenschaftlicher Beirat:
Ass. Prof. Dr. Siegfried Jäger (Medizinische Universität Wien)
Univ. Prof. Dr. Reinhart Jarisch (Floridsdorfer Allergie Zentrum)
Mag. Matthias Werchan (Charité Berlin)
Prof. Dr. med. Karl-Christian Bergmann (Charité Berlin)
Quellen:
Österreichischer Pollenwarndienst, Medizinische Universität Wien, Österreich
Charité, Allergie-Zentrum-Charité, Klinik für Dermatologie, Venerologie und Allergologie, Berlin, Deutschland
Wikipedia
www.alles-zur-allergologie.de
22 Jahre Blüh- und Fruktifikationsuntersuchungen der Waldbaumarten im Lehrforst Ofenbach/Rosalia. R. Litschauer. 2010. Bundesforschungs- und Ausbildungszentrum für Wald, Naturgefahren und Landschaft, BFW-Berichte 144, 36 pp.
Waldbau auf soziologisch-ökologischer Grundlage. H. Mayer 1977. Gustav Fischer Verlag, Stuttgart – New York, 482 pp.