Collinsia Nutt.
Collinsia is a North American genus with ca. 20 species. Its center of diversity lies in California. Recent molecular data demonstrated that diversity in Collinsia is greater than previously documented (Baldwin & al. 2011). A few species are cultivated as ornamentals in Europe (e.g. Jäger & al. 2008), C. heterophylla by far being the most widespread.
Literature:
Baldwin B.G., Kalisz S. & Armbruster W.S. (2011) Phylogenetic perspectives on diversification, biogeography, and floral evolution of Collinsia and Tonella (Plantaginaceae). Am. J. Bot. 98(4): 731-753. [available online at: http://www.amjbot.org/content/98/4/731.full.pdf+html]
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Newsom V.M. (1929) A revision of the genus Collinsia (Scrophulariaceae). Botanical Gazette 87: 260-301.
Raman S. (1990) The trichomes on the corolla of the Scrophulariaceae: 7. Tribe Cheloneae Benth. Beitr. Biol. Pfl. 65(2): 223-234.