Ambrosia artemisiifolia
Common ragweed, Common Ragweed
Family: Asteraceae · Type: annual · Not Native
Common ragweed is a naturalized annual found in the Klamath Ranges, northern California Rocky Forests, northern and central Sierra Nevada, Sacramento Valley, southern Coast Ranges, southern California Coast, and Peninsular Ranges in disturbed sites at elevations below 1,050 meters. Flowering from July to October, this plant produces small green flowers in raceme-like clusters with asymmetric heads. Growing with much-branched stems up to 70 centimeters tall that can be occasionally marked with red or black, it spreads widely in disturbed landscapes. Its leaves are deeply divided with 2 to 3 pinnate segments, widely ovate and measuring 3 to 12 centimeters long, covered in strigose and soft hairs. The fruit develops as a spiny green to brown bur 2 to 4 millimeters long, with 4 to 12 generally blunt spines arranged in a single whorl.
Habitat: Uncommon. Disturbed sites
Bloom period: Jul-Oct
Elevation: < 1050 m
Bioregions: KR, CaRF, n&c SN, ScV, SCoRO, SCo, PR
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.