Ragweed

Ambrosia dumosa

The grapes herbs or ragweed (Ambrosia ) are a genus of plants of the daisy family (Asteraceae). The botanical genus name is derived from Greek a- brotos immortal, compare Ambrosia.

Individual species of the genus Ambrosia verwildern easily spread very efficiently and invasive and are difficult to eradicate (hence the generic name ). Some species cause a variety of damage to health, nature and economy.

Description

Ambrosia species are one-to perennial herbaceous plants or shrubs that plant height of 10 to over 400 cm reach. They usually form rhizomes. The stems are usually erect, rarely decumbent, often they are branched. The leaves are very diverse. The AC or against permanent leaves are petiolate or sessile. The leaf blade is simple to pinnate. The leaf edges are smooth to toothed.

Ambrosia species are mostly monoecious getrenntgeschlechtig ( monoecious ). In branched inflorescences many usually unisexual, basket- shaped partial inflorescences stand together. The head floors are discus -shaped. The often black achenes have no pappus.

Types and occurrence

The genus includes 30 to 40 species in North America are predominantly domestic.

In Europe occur in particular as highly allergenic known Beifußblättrige ragweed (Ambrosia artemisiifolia ) and the rare -leaved ragweed (Ambrosia trifida ) and the Perennial ragweed (Ambrosia psilostachya ) as neophytes. In Europe, the spread is usually through contaminated bird seed, seed mixes, cereals and other seeds. Due to the highly allergenic effect in combination with the rapid spread of the plant every citizen in Switzerland, Italy and Hungary even legally obliged to report them and to destroy as well. Violations of this rule are fined.

Swell

• Description in the Flora of North America. (English )
• Ambrosia.de