Some of the earlier European horticultural sources (e.g., Rehder, 1940; Krüssmann, 1978) designated the cut-leaved selection of Sambucus nigra subsp. nigra (European Elderberry or Elder) as ‘Laciniata’, which may have been named as early as 1650.  ‘Acutiloba’, a later cut-leaved selection, was derived from Sambucus nigra subsp. canadensis (American Elderberry or Elder). However, in time 'Laciniata' and 'Acutiloba' seemed to have morphed into synonyms, but not always, (e.g., International Dendrology Soc., Trees and Shrubs Online). The two subspecies, nigra and canadensis, are "closely related and so similar in morphology that specimens cannot always be unambiguously identified, which argues against recognition at the species level" (Applequist, 2015).  Some have classified them as conspecific.  This may have contributed to the view that the two cultivars are essentially the same plant.