Rowan Several of the Asian species are widely cultivated as ornamental trees. North American native species in the subgenus "Sorbus (Sorbus)" include the American mountain-ash "Sorbus americana" and Showy mountain-ash "Sorbus decora" in the east and Sitka mountain-ash "Sorbus sitchensis" in the west. Numerous hybrids, mostly behaving as true species reproducing by apomixis, occur between rowans and whitebeams; these are variably intermediate between their parents but generally more resemble whitebeams and are usually grouped with them (q.v.). Rowans are excellent small ornamental trees for parks, gardens and wildlife areas. Several of the Chinese species, such as White-fruited rowan ("Sorbus glabrescens") are
Sorbus chamaemespilus in corymbs 3–4 cm diameter. The fruit is an oval red pome 10–13 mm diameter. It is the sole species in a group that has been called genus "Chamaemespilus" or "Sorbus" subgenus "Chamaemespilus", distinguished from other subgenera of "Sorbus" by the pink (not white) flowers with forward-pointing petals (not opening flat). More recently, it has become clear that the simple-leafed species traditionally included in "Sorbus" form a monophyletic group, and this species could be included in a clade called "Aria" (genus "Aria" or "Sorbus" subgenus "Aria"). Sorbus chamaemespilus Sorbus chamaemespilus, the false medlar or dwarf whitebeam, is a species of