''Sorbus'' is a genus of over 100 species of trees and shrubs in the rose family,

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus ...

. Species of ''Sorbus'' (''s.l.'') are commonly known as whitebeam,

rowan The rowans ( or ) or mountain-ashes are shrubs or trees in the genus ''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, r ...

(

mountain-ash The rowans ( or ) 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 ...

) 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 treatmentsRobertson, K. R., J. B. Phipps, J. R. Rohrer, and P. G. Smith. 1991. A Synopsis of Genera in Maloideae (Rosaceae). ''Systematic Botany'' 16: 376–394.McAllister, H. 2005. The Genus ''Sorbus'': Mountain Ash and Other Rowans. Richmond, Surrey, UK: Royal Botanic Gardens, Kew.Potter, D., T. Eriksson, R. C. Evans, S.-H. Oh, J. E. E. Smedmark, D.R. Morgan, M. S. Kerr, and C. S. Campbell. (2007). Phylogeny and classification of Rosaceae. ''Plant Systematics and Evolution''. 266(1–2): 5–43.Campbell C. S., R. C. Evans, D. R. Morgan, T. A. Dickinson, and M. P. Arsenault. 2007. Phylogeny of subtribe Pyrinae (formerly the Maloideae, Rosaceae): Limited resolution of a complex evolutionary history. ''Pl. Syst. Evol.'' 266: 119–145. classify ''Sorbus'' in a narrower sense to include only the pinnate leaved species of

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

''Sorbus'', raising several of the other subgenera to generic rank. ''Sorbus'' is not closely related to the true ash trees which belong to the genus ''

Fraxinus ''Fraxinus'' (), common name, commonly called ash, is a genus of flowering plants in the olive and lilac family, Oleaceae. It contains 45–65 species of usually medium to large trees, mostly deciduous, though a number of Subtropics, subtropic ...

'', although the leaves are superficially similar.

Genus

As treated in its broad sense, the genus is divided into two main and three or four small subgenera (with more recent generic assignments in parentheses): *''Sorbus'' subgenus ''Sorbus'' (genus ''Sorbus'' s.s.), commonly known as the

(primarily in the UK) or mountain-ash (in Ireland, North America and the UK), with compound leaves usually hairless or thinly hairy below; fruit carpels not fused; the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

is ''

Sorbus aucuparia ''Sorbus aucuparia'', commonly called rowan (UK: /ˈrəʊən/, US: /ˈroʊən/) and mountain-ash, is a species of deciduous tree or shrub in the rose family. It is a highly variable species, and botanists have used different Circumscription (taxo ...

'' (European rowan). Distribution: cool-temperate

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. (Genus ''Sorbus'' s.s.) *''Sorbus'' subgenus ''Aria'' (genus ''Aria''), the whitebeam, with simple leaves usually strongly white-hairy below (hence the name, from German ''Weissbaum'', 'white tree'); fruit carpels not fused; the type is ''

Sorbus aria ''Sorbus aria'' ( syn. ''Aria nivea''), the whitebeam or common whitebeam, is a deciduous tree, the type species of the subgenus ''Sorbus'' subg. ''Aria'' of the genus ''Sorbus''. It is native to most of Europe as well as North Africa (Algeria, M ...

'' (common whitebeam). Distribution: temperate Europe & Asia. *''Sorbus'' subgenus ''Micromeles'' (genus ''Micromeles''), an indistinct group of a few east Asian species (e.g. '' Sorbus alnifolia'', Korean whitebeam) with narrow leaves; doubtfully distinct from and often included in subgenus ''Aria''. Distribution: temperate northeast Asia. *''Sorbus'' subgenus ''Cormus'' (genus ''Cormus''), with compound leaves similar to subgenus ''Sorbus'', but with distinct fused carpels in the fruit; just one species, '' Sorbus domestica'' (True Service Tree). Distribution: North Africa, warm-temperate Europe, West Asia. *''Sorbus'' subgenus ''Torminaria'' (genus ''Torminalis''), with rather maple-like lobed leaves with ''pointed'' lobes; fruit carpels not fused; just one species, '' Sorbus torminalis'' (Wild Service Tree). Distribution: temperate Europe, south to the mountains of North Africa and east to the Caucasus ranges. *''Sorbus'' subgenus ''Chamaemespilus'' (genus ''Chamaemespilus''), a single shrubby species '' Sorbus chamaemespilus'' (false medlar) with simple, glabrous leaves and pink flowers with erect sepals and petals. Distribution: mountains of southern Europe. *''Sorbus'' subgenus ''Umbellata'' (genus ''Umbellata''), Sorbus umbellata ssp. flabellifolia has oval with saw-like indentations along the upper edges of the leaf. It produces an edible but not high quality fruit. Distribution: mountains of Lebanon and specifically Ehden and Shouf Nature Reserves at elevations between 1300 to 1800 meters. *Hybrids are common in the genus, including many between the subgenera; very often these hybrids are

apomictic In botany, apomixis is asexual reproduction without fertilization. Its etymology is Greek for "away from" + "mixing". This definition notably does not mention meiosis. Thus "normal asexual reproduction" of plants, such as propagation from cuttin ...

(self-fertile without pollination), so able to reproduce clonally from seed without any variation. This has led to a very large number of microspecies, particularly in western Europe (including Britain) and parts of China. ''Sorbus'' species are used as food plants by the larvae of some moth species—see list of Lepidoptera that feed on ''Sorbus''. '' Sorbus domestica'' is used to flavour some apple wines, see '' Apfelwein''.

Species

Uses

Ornamental trees

''Sorbus'' species are cultivated as ornamental trees for parks and gardens and as avenue trees, and have given rise to several

cultivars A cultivar is a type of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and when Plant propagation, propagated retain those traits. Methods used to propagate cultivars include: division, root and st ...

. The following, of mixed or uncertain parentage, have gained the Royal Horticultural Society’s

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

: *’Eastern Promise’ (purple autumn colour, pink berries) *’Leonard Messel’ (small tree to 4m, pink berries) *’Wisley Gold’ (yellow berries)

Gallery

File:Punetav pihlapuu.jpg, Red rowan File:Rowan in the garden of Eastern Siberia.jpg, Rowan in the garden of Eastern Siberia

References