Ambrosia artemisiifolia

Flower name
Ambrosia artemisiifolia
Scientific name
Ambrosia artemisiifolia
Alias豚草
Place of originNorth America
Place of floweringFields and footpaths
Flowering seasonJuly, August, September, October

What is Ambrosia artemisiifolia

Ambrosia artemisiifolia or pigweed(scientific name: Ambrosia artemisiifolia) is an annual grass in the family Asteraceae. It is a naturalized plant that was introduced to Japan in the early Meiji period (around 1877). Ragweed is a causative agent (allergen) of autumn hay fever, which occurs from July to October, and causes nasal, eye, respiratory, and allergic diseases.

Causative agents of hay fever (season when they are scattered)
Cedar (spring), cypress (spring), birch (summer), rice (summer), ragweed (fall) Mugwort (autumn), canola (autumn), cedar (winter)

The genus name "Ambrosia" refers to the food of the gods in Greek mythology, which is said to give immortality to those who eat it.
The species name "artemisiifolia" is derived from "artemisii (wormwood)" + "folia (leaf)," meaning that the leaves resemble wormwood.

Common name: Ambrosia artemisiifolia, scientific name: Ambrosia artemisiifolia, other names: Bitterweed, Ambrosia, Common Ragweed, Ragweed, hogweed, Annual ragweed, hogweed (Chinese name) , Stem leaves: soft hairy, Phyllotaxis: opposite down stem, alternate up stem, Leafiness: soft, Leaf shape: bifid, deeply lobed, dioecious, Male flowers [Inflorescence form: narrow, grossly inflorescent, narrowly pubescent, dorsal to ovate, dioecious Inflorescence form: elongate raceme, corolla: capitulum, capitulum diameter: 0.3-0.4 cm], Female flowers [Corolla form: capitulum, flowering site: 2-3 flowers clustered in leaf axils at base of male inflorescence], Flower color: yellow, Flowering season: July-October, Small flower diameter: 0.2-0.3 cm, Wind-pollinated, Fruit type: thin fruit, Note: Designation: "Invasive alien species requiring attention