National Plant Data Center, NRCS, USDA. Baton Rouge, LA 70874-4490 USA. http://plants.usda.gov
Reference for:
Carduus
Source:
The PLANTS Database
Acquired:
2000-01-21
Notes:
National Plant Data Center, NRCS, USDA. Baton Rouge, LA 70874-4490 USA. http://plants.usda.gov
Reference for:
Carduus
Source:
Asteraceae of North America Update
Acquired:
2010-05-13
Notes:
Update coordinated by the International Compositae Alliance (TICA) (http://www.compositae.org/) through the Smithsonian Institution in collaboration with the USDA National Plant Data Center