The Canadian Toadflax (Nuttallanthus canadensis) is one of three Nuttallanthus species that grow in this area. The other species are the Apalachicola toadflax (Nuttallanthus floridanus) and the Texas Toadflax (Nuttallanthus texanus).
Nuttallanthus canadensis is known by several common names; Canada Toadflax, Canadian Toadflax, Oldfield Toadflax, Old-field Toadflax, or Blue Toadflax. It is the first toadflax to bloom each year. N. floridanus and N. texanus bloom later.
When I first encountered these species, it took me some time and observation to be able to differentiate between them. I thought the variation was due to variations in growth patterns resulting from different qualities of soil. However, the flowers of these species clearly differ in size, color, and color pattern and can be identified on the basis of these characteristics.
They grow in patches along roads – where these photos were taken – and in fields.
An individual flowering stem
An individual flowering stem from above
Each flower is about 1/4-inch in long. Both the purple and white colors are solid; they show no sign of color veins.
Canadian Toadflax (Nuttallanthus canadensis) grows in the eastern Canadian provinces and United States has been introduced to and become established in Washington state, Oregon and California.
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- United States Department of Agriculture Plants Database: Nuttallanthus canadensis (Canadian Toadflax)
- Southeastern Flora: Oldfield toadflax (Nuttallanthus canadensis)
- 2010: Year Of The Wildflower