https://kingcounty.gov/legacy/services/environment/animals-and-plants/noxious-w…

King County Department of Natural Resources (Washington). Water and Land Resources Division.

https://ipm.ucanr.edu/PMG/weeds_intro.html

University of California. Statewide Integrated Pest Management Program.

The UC IPM Weed Photo Gallery includes many, but not all, weed species commonly found in California farms and landscapes.