Lopezia Cav.
Lopezia is a genus of 22 species, all native to Central-America. Its center of diversity clearly is in Mexico. One species, Lopezia racemosa, is more or less widely grown as an ornamental in Europe although its value is restricted (unshowy annual with small corollas).
Literature:
Hoch P.C. (1997) Lopezia. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge.
O’Kane S.L. Jr. & Schaal B.A. (1998) Phylogenetics of Lopezia (Onagraceae): evidence from chloroplast DNA restriction sites. Syst. Bot. 23: 5-20.
Plitmann U., Raven P.H. & Breedlove D.E. (1973) The systematics of Lopezieae (Onagraceae). Ann. Missouri Bot. Gard. 60: 478-563.
Wagner W.L., Hoch P.C. & Raven P.H. (2007) Revised classification of the Onagraceae. Syst. Bot. Monogr. 83: 1-240.