The whitebeams are members of the Rosaceae family, in genus Sorbus subgenus Aria. 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 Fon… (More on Whitebeam)