Sorbus is a genus of about 100–200 species of trees and shrubs in the Rose family Rosaceae. Species of Sorbus (s.l.) are commonly known as whitebeam, rowan, service tree, and mountain-ash. The exact number of species is disputed depending on the circumscription of the genus, and also due to the number of apomictic microspecies, which some treat as distinct species but others group in a smaller number of variable species. Recent treatments treat Sorbus in a narrower sense to include only the pinnate leaved species of subgenus Sorbus, raising several of the other subgenera to generic rank. Sorbus is unrelated to the true ash trees which belong to the genus Fraxinus, although the leaves are superficially similar.