In the 1920's and later a certain Isabelle Preston did a whole lot of hybridizing of lilacs in Ottawa, Canada. The Preston hybrids are usually the cross of the Late Lilac (S. villosa) x the Nodding Lilac (S. reflexa), both Chinese species with the hybrid looking more like the Late Lilac species. The cross is Syringa x prestoniae. However, she also did some crosses with the Hungarian Lilac from central & southern Europe (S. josikaea) x the Nodding Lilac (S. reflexa) to produce S. x josiflexa that is also called a Preston Hybrid. One source says this later cross brought about this James MacFarlane cultivar while other sources say it was the first and more common cross with the Late Lilac. I only occasionally see one of these later blooming lilacs, that bloom 2 to 3 weeks later than the Common Lilac, in average yards in the Midwest or Eastern US; and usually it is James MacFarlane as being the most common cultivar. I sold a few James MacFarlane Lilacs back in the Chicago ,IL, area in the 1980's at two different nurseries. These crosses and the straight species of these lilacs do not have really good fragrance in their flowers like the Common Lilac.