Family: Asteraceae Aster Family
Genus: Ambrosia Ragweed
Genus of about 15 species of annual herbs with unisexual flower heads and producing pollen that is one of the chief causes of hay fever. Found mainly in North and South America.
Scientific Name: Ambrosia psilostachya DC.
Common Name(s): Western Ragweed, Perennial Ragweed, Cuman Ragweed
Growth Type: annual/perennial
Species Description:
Click on the thumbnails to view large image.
 | Caption: Western ragweed's bushy growth habit.
ID: Hrb-AMBPS-002
Source: 35mm slide (photo)
Credit:
Keyword(s): flowering, inflorescense, mature
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 | Caption: Western ragweed's male spike inflorescence at the top of the stems. It also has alternate or opposite deeply lobed leaves.
ID: Hrb-AMBPS-001
Source: 35mm slide (photo)
Credit:
Keyword(s): flowering, inflorescense, leaf, mature
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 | Caption: Western ragweed's male spike inflorescence is located at the end of the stem and the female inflorescence is located in the upper leaf axils. Both male and female flowers are located on the same plant. It also has alternate or opposite deeply lobed leaves and seeds with spikes at the top.
ID: Hrb-AMBPS-003
Source: 35mm slide (illustration)
Credit:
Keyword(s): flowering, inflorescense, leaf, mature, seed, stem
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