Blue Toadflax (Nuttallanthus canadensis)

Slender, smooth, tap-rooted biennial or winter annual, 8-24" tall, with an errect, almost leafless flowering stem arising from a basal rosette of prostrate, leafy stems. 

Leaves: linear, 0.4-1.0" long, alternate on flowering stem, opposite on prostrate stems. 

Flowers: blue to lavender, 0.2-0.5" long,; 2-lipped corola with a narrow spur, lower lip has a double-humped, white palate and much exceeds the upper lip; borne in 1 to several racemes. 

Bloom time: April - May.

Where found: roadsides, fields, and thin soil of rockout crops. Widespread in eastern North America and the Pacific Coast states. Widely scattered across TN. Occasional. 

Note: Plans in the Linaria genus are also called 'toadflaxes' because the flower opens its mouth like a toad when squeezed in a certain way. The Linaria genus is comprised mostly of plants from Eurasia, a number of them cultivated. The North American species have blue (rather than yellow) flowers with a lower lip that is greatly enlarged relative to the upper one.