The whitebeams are members of the family Rosaceae, comprising the genus Aria. They are deciduous trees with simple or lobed leaves, arranged alternately. They are related to the rowans, and many of the endemic restricted-range apomictic microspecies of whitebeam in Europe are thought to derive from hybrids between the common whitebeam and the European rowan. Some are also thought to be hybrids with the wild service tree, and the service tree of Fontainebleau found in French woodlands.
Whitebeam
Cross-section of a whitebeam trunk
The rowans or mountain-ashes are shrubs or trees in the genus Sorbus of the rose family, Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the Himalaya, southern Tibet and parts of western China, where numerous apomictic microspecies occur. The name rowan was originally applied to the species Sorbus aucuparia and is also used for other species in the genus Sorbus.
Rowan
White-fruited rowan Sorbus glabrescens, a Chinese species with white fruit
Mature European rowan tree
Rowan flowers