The
whitebeams are members of the
Rosaceae family, comprising subgenus
Aria of genus
Sorbus, and hybrids involving species of this subgenus and members of subgenera
Sorbus,
Torminaria and
Chamaemespilus. They are
deciduous trees with simple or lobed leaves, arranged alternately. They are related to the
rowans (
Sorbus subgenus
Sorbus), and many of the
endemic restricted-range
apomictic microspecies of whitebeam in Europe are thought to derive from hybrids between
S. aria and the European rowan
S. aucuparia; some are also thought to be hybrids with the
wild service tree S. torminalis, notably the service tree of Fontainebleau
Sorbus latifolia in French woodlands.