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In 1920 Dr Isabella Preston of the Central Experimental Farm, Ottawa, crossed S. reflexa with S. villosa and produced a wide range of most desirable late-flowering lilac hybrids, combining in different degrees the various characteristics of the parent species. The cross has been repeated and many cultivated varieties are now available. See further on pp. 550–1. For the history of this group see Ornamental Flowering Trees and Shrubs, R.H.S. Conference Report (1940), pp. 135–40.