The rowans or mountain-ashes are shrubs or trees in the genus Sorbus of the rose family, Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the Himalaya, southern Tibet and parts of western China, where numerous apomictic microspecies occur. The name rowan was originally applied to the species Sorbus aucuparia and is also used for other species in Sorbus subgenus Sorbus.
Sorbus is a genus of over 100 species of trees and shrubs in the rose family, Rosaceae. Species of Sorbus (s.l.) are commonly known as whitebeam, rowan (mountain-ash) and service tree. 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 classify Sorbus in a narrower sense to include only the pinnate leaved species of subgenus Sorbus, raising several of the other subgenera to generic rank.
The whitebeams are members of the family Rosaceae, comprising subgenus Aria of genus Sorbus, and hybrids involving species of this subgenus and members of subgenera Sorbus, Torminaria and Chamaemespilus. They are deciduous trees with simple or lobed leaves, arranged alternately. They are related to the rowans, and many of the endemic restricted-range apomictic microspecies of whitebeam in Europe are thought to derive from hybrids between S. aria and the European rowan S. aucuparia; some are also thought to be hybrids with the wild service tree S. torminalis, notably the service tree of Fontainebleau Sorbus latifolia in French woodlands.
Sorbus torminalis, with common names wild service tree, chequers, and checker tree, is a species of tree in the mountain ash or rowan genus (Sorbus) of the rose family (Rosaceae), that is native to Europe, parts of northern Africa and western Asia.
The Arran whitebeams are species of whitebeam endemic to the island of Arran, Ayrshire, Scotland.
Sorbus pseudomeinichii, known as false rowan and Catacol whitebeam, is a rare tree endemic to the Isle of Arran in south west Scotland. It is believed to have arisen as a hybrid of the native rowan and the cut-leaved whitebeam which is in turn a rowan/Arran whitebeam hybrid. Until 2020 only two specimens of the Catacol whitebeam were known, at the time making it the rarest tree not only in Scotland, but joint rarest in the world with Wood's cycad, both with only one specimen living. A third was recorded as a sapling, but is believed to have been destroyed by deer. A seedling and grafted plants have also been grown in Edinburgh.
Sorbus anglica, the English whitebeam, is a species of whitebeam tree in the family Rosaceae. It is uncommonly found in Ireland and the United Kingdom, with an entire British population estimated at about 600 individuals.
Sorbus vexans is a rare tree in the family Rosaceae. It is endemic to England. It is found along the coast between Culbone in Somerset and an area just west of Trentishoe in Devon. It can be seen in the Exmoor National Park. It is threatened by habitat loss.
Sorbus wilmottiana, the Willmott's whitebeam, is a species of whitebeam in the family Rosaceae. It is endemic to England, and is found in the Avon Gorge, in Somerset and Gloucestershire. It is threatened by habitat loss.
Scandosorbus intermedia, the Swedish whitebeam, is a species of whitebeam found in southern Sweden, with scattered occurrences in Estonia, Latvia, easternmost Denmark (Bornholm), the far southwest of Finland, and northern Poland.
Sorbus × hybrida, the oakleaf mountain ash, Swedish service-tree or Finnish whitebeam, is a hybrid species of whitebeam native to Norway, eastern Sweden, southwestern Finland, and locally in Latvia.
Sorbus mougeotii, the Vosges whitebeam or Mougeot's whitebeam, is a species of whitebeam native to the mountains of central and western Europe from the Pyrenees east through the Alps to Austria, and north to the Vosges Mountains.
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 and the rowan. It was first discovered in 1893 by Augustin Ley, the vicar of Sellack in Herefordshire who travelled widely in Wales.
Cefn Cil Sanws is a hill in the Brecon Beacons National Park within the county borough of Merthyr Tydfil in south Wales. The summit at 460m above sea level is crowned by a trig point. The steep cliffs of Darren Fawr and Darren Fach defend its western side which drops down into Cwm Taf. A major limestone quarry is worked on the southeastern side of the hill. An unexpected feature at this altitude is Merthyr Tydfil Golf Course which extends high onto the eastern and southern slopes of the hill.
Karpatiosorbus admonitor, previously classified as Sorbus admonitor and also called the no parking whitebeam, is a species of whitebeam tree found in Devon, United Kingdom. It is known only from the Watersmeet Valley at Lynton, with two stray plants growing on the coast above Sillery Sands, Countisbury.
Sorbus hibernica, the Irish whitebeam, is a species of whitebeam endemic to Ireland. It occurs in most counties, usually as scattered individuals, or in small groups. It is sometimes treated as a species in the genus Aria, as Aria hibernica.
Sorbus porrigentiformis, the grey-leafed whitebeam, is a species of whitebeam endemic to England and Wales.
Sorbus scannelliana, Scannell's whitebeam, is a species of whitebeam endemic to Ross Island near Killarney in southwest Ireland. It is one of the rarest tree species in the world; only five individual plants are known.
Sorbus leighensis, the Leigh Woods whitebeam, is a rare species of whitebeam, a flowering plant in the rose family.
