Rowan Rowan 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 mountains of western China and the Himalaya, where numerous apomictic microspecies occur. The name "rowan" was originally applied to the species "Sorbus aucuparia" and is also used for other species in "Sorbus" subgenus "Sorbus". Formerly, when a wider variety of fruits were commonly eaten in Europe and North America, "Sorbus" was a domestically used fruit throughout these regions. It is still used in
Sorbus torminalis the bark on old trees. The species has sometimes been placed in its own genus, "Torminalis". Recent molecular phylogenetics confirms an earlier taxonomic opinion that the genus "Sorbus" as defined in the broad sense is not monophyletic, but the simple-leafed species traditionally included in "Sorbus" are a monophyletic group; this species would be included in a clade called "Aria" (genus "Aria" or "Sorbus" subgenus "Aria") as the species "Aria torminalis" Beck. It is a sexually reproducing diploid species that forms diploid and polyploid hybrids with members of subgenus "Aria" (whitebeams). A number of often very localised stable apomictic polyploid species