Sorbus × hybrida by thrushes and waxwings, which disperse the seeds. It is a tetraploid species of hybrid origin between "S. aucuparia" (European rowan) and "S. intermedia" (Swedish whitebeam), the latter being a tetraploid triple hybrid between "S. aucuparia", "S. torminalis", and either "S. aria" or one of its close relatives. "S. intermedia" differs from "S. hybrida" in having the leaves less deeply lobed with no separate leaflets. Closely related "Sorbus meinichii" is a triploid or tetraploid species of hybrid origin between "S. hybrida" and "S. aucuparia" and differs in having the basal four to six pairs of lobes cut right to the
Fraxinus excelsior narrow crown. The bark is smooth and pale grey on young trees, becoming thick and vertically fissured on old trees. The shoots are stout, greenish-grey, with jet black buds (which distinguish it from most other ash species, which have grey or brown buds). The leaves are opposite, long, pinnately compound, with 7–13 leaflets with coarsely serrated margins, elliptic to narrowly elliptic, long and broad and sessile on the leaf rachis. There are no stipules. These features distinguish ash from mountain ash ("Sorbus aucuparia") in which the leaves are alternate with paired stipules. The leaves are often among the last to