Sorbus aria x aucuparia (S. x thuringiaca)
A small tree occurring sporadically where the parent species grow together, and as a planted tree in woodland and parks. It is partially fertile and can set viable seed. Lowland.
This hybrid may be under-recorded, but appears to be genuinely rare as a native tree.
Widespread in Europe and perhaps more frequent as a planted tree than as a spontaneous hybrid.
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections.
A hardcopy can be purchased from the Centre for Ecology and Hydrology.