Sorbus Sorbus 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
Sorbus aucuparia but wide and the plant often grows multiple trunks. A trunk is slender and cylindrical and reaches up to 40 cm in diameter, and the branches stick out and are slanted upwards. The bark of a young "S. aucuparia" is yellowish gray and gleaming and becomes gray-black with lengthwise cracks in advanced age; it descales in small flakes. Lenticels in the bark are elongated and colored a bright ocher. The plant does not often grow older than 80 years and is one of the shortest-lived trees in temperate climate. Wood of "S. aucuparia" has a wide reddish white sapwood and