1. Washington State Noxious Weed Control Board
2. Center for Invasive Plant Management
3. Palouse Prairie Foundation
4. PNW Weed Management Handbook
5. Field Guide to Noxious and Other Selected Weeds of British Columbia
6. Cornell University Poisonous Plant Database
7. Washington Department Fish & Wildlife
8. USFS Invasive Species Program
9. Ten Most Poisonous Plants for Horses
10. Calphotos; Browse plants by Scientific Name
11. Pacific Northwest Wildflowers
12. Federal and State Invasive Species Activities
13. Central Washington Native Plants
14. BLM Learning Landscapes
15. California Biological Control