Gaura lindheimeri Engelm. & A.Gray (Boston Journal of Natural History 5 1845) is the basionym.
The species was transferred to the genus Onagraceae as Oenothera lindheimeri (Engelm. & A.Gray) W.L.Wagner & Hoch in Systematic Botany Monographs 83, page 213 in September 2007.
It's botanical accepted name is now Oenothera lindheimeri.
However, if you are looking to buy the plant, I see (in 2013) that nurseries list the plant as Gaura; I don't see any offered as Oenothera.
