Philadelphus. There are several species and many cultivars.

Much appreciated. Thank you for your response.

If you want it, be sure to get a cultivar that has a wonderful fragrance. Some of the newer, fancier ones are lacking.

Right^... Old-fashioned mockorange has fallen into disuse in the trade, but shouldn't be. A great old shrub.

The fragrance of these has always varied. And none of the newer introductions are any fancier than the best ones raised by the Lemoine nursery in France during the early 20th century. The popular 'Belle Etoile' for instance was being grown by 1930.

The point being, I think, buy it in bloom from a nursery if you can and sniff before you pay.