Sorbus minima Sorbus minima Sorbus minima, commonly known as the lesser whitebeam or least whitebeam, is a shrub belonging to the subgenus "Aria" (whitebeams) in the genus "Sorbus". It is endemic to Wales where it grows at a few sites in Breconshire. It is an apomictic microspecies which reproduces asexually and so is reproductively isolated from its close relatives such as the Swedish whitebeam, "S. intermedia". It probably originated as a hybrid between the rock whitebeam ("S. rupicola") and the rowan ("S. aucuparia"). It was first discovered in 1893 by Augustin Ley, the vicar of Sellack in Herefordshire who travelled widely in
Arran whitebeams between "S. arranensis" and the mountain ash ("S. aucuparia"). The "Sorbus" group are apomictic, producing viable seed without the need for pollination and fertilisation. Each time this hybrid cross occurs a new clone is effectively produced. Smart showed by using physical characteristics that the species were separate and not a result of random variation. Some overlap does however occur and this suggests that some hybridising may occur between the two species. A number of other "Sorbus" species have been produced in this way, such as the Devon whitebeam, the Bristol whitebeam, the Cheddar whitebeam, Irish whitebeam, Lancaster whitebeam, etc. All