(Cardot) Hand.-Mazz.
Description
Sorbus thibetica is a Sino-Himalayan whitebeam distributed along the eastern Himalaya and adjacent China, from Nepal through northern India, Sikkim and Bhutan into south-western China (Xizang, Yunnan) and northern Myanmar; its roughly 470 georeferenced occurrences include numerous cultivated records in Britain and northern Europe (GB, NO, DK), reflecting its long-standing horticultural use. It grows in temperate and subalpine forest, woodland margins, rocky slopes and open hillsides, generally between about 2500 and 3600 m. The tree photographed at Pele-La in Bhutan at 3000 m in October, in autumn fruit and leaf-colour, is typical of its cool, montane forest habitat.
It is a deciduous tree to 10-20 m, with a rounded crown and grey bark; the stout twigs and buds are densely white-tomentose when young. The leaves are simple (not pinnate), broadly elliptic to obovate, entire-leaved members of the Aria group, dark green and glabrescent above but persistently covered beneath with a thick, silvery-white felted tomentum, the margins finely and shallowly toothed. The white flowers are borne in flat-topped corymbs, each with five petals, numerous stamens and an inferior ovary. The fruit is a small subglobose pome, ripening orange-brown to russet and bearing scattered lenticels, typical of the simple-leaved whitebeams.
Sorbus thibetica belongs to the Aria group of simple-leaved whitebeams (sometimes segregated as the genus Aria), distinct from the pinnate-leaved rowans of Sorbus sensu stricto. The selection 'John Mitchell', with very large leaves, is widely grown ornamentally. Apomixis and hybridisation complicate species limits throughout the group. Widespread and frequent, it is not considered threatened.
Author: (Cardot) Hand.-Mazz. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Nepal, McAllister's The Genus Sorbus: Mountain Ash and other Rowans