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 aucuparia Pliocene age. Fruit of "S. aucuparia" were used in the past to lure and catch birds. To humans, the fruit are bitter, astringent, laxative, diuretic, cholagogue, prevent scurvy, and the parasorbic acid irritates the gastric mucosa. Pharmacist Mannfried Pahlow wrote that he doubted the toxicity of the fruit but advised against consuming large amounts. The fruit contain sorbitol, which can be used as a sugar substitute by diabetics, but its production is no longer relevant. "Sorbus aucuparia" fruits have been used in the traditional Austrian medicine internally (as tea, syrup, jelly or liqueur) for treatment of disorders of the respiratory