Nemesia caerulea Hiern, Fl .Cap. 4(2): 191 1904. ?;
Nemesia caerulea is a blue- to purple- flowered herbaceous perennial member of the Plantaginaceae family. The plant is native to the Cape Floristic Province of southwestern South Africa, where it grows at low elevations on fully exposed north-facing and northwest-facing slopes in association with other native grasses and herbs. Its chromosome number is 2n=18.
It produces many small flowers in shades of pink, blue and white (the Latin caerulea means “dark blue”). The flowers are two-lipped, the upper lip with four lobes and the lower lip with two lobes. In cultivation the two lips are often different colours.
(From Wikipedia on 29.8.13)
Scrophulariaceae Fortnight : 13082013 ARK-10 : Nemesia caerulea from Chicago, USA – May 2013 : Attachments (3). 2 posts by 2 authors.
Attached are pictures of what I found on googling to be Nemesia caerulea captured in Chicago, USA in May 2013.
Could you please confirm the ID?
The Plant List (unresolved) Missouri botanical garden Wikipedia