''Sorbus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of over 100

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of trees and shrubs in the rose

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Rosaceae Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus '' Rosa''. The family includes herbs, shrubs, and trees. Most species are deciduous, but som ...

. Species of ''Sorbus'' ('' s.str.'') are commonly known as rowan or mountain-ash. The genus used to include species commonly known as whitebeam, chequer tree and service tree that are now classified in other genera (see below). The genus ''Sorbus'', as currently circumscribed, includes only the pinnate leaved species of former

subgenus In biology, a subgenus ( 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 the ge ...

''Sorbus''. ''Sorbus'' is not closely related to the true ash trees which belong to the genus '' Fraxinus'', although the leaves are superficially similar.

Genus

As treated in its broad sense, the genus was traditionally divided into several subgenera, however, this treatment was found to be

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

, comprising two disparate lineages within the Malinae subtribe. Consequently, each of the former subgenera have since been elevated into genera in their own right, with the genus name ''Sorbus'' retained only for the rowans. Additionally, it was recognised that despite a comparably large genetic distance between them, the genera ''Sorbus (''sensu stricto), ''Aria, Chamaemespilus'' and ''Torminalis'' have interbred extensively, in various combinations, which lead to the recognition of an additional five intergeneric hybrid genera.Rushforth, Keith (2018)
The Whitebeam problem, and a solution.
''Phytologia'' 100(4): 222-247. 21 December 2018. ;''Sorbus'' (''Sorbus'') * now genus '' Sorbus'' s.s., are commonly known as the rowan (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 is '' Sorbus aucuparia'' (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 by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

. ;''Sorbus'' (''Aria'') * now genus ''

Aria In music, an aria (, ; : , ; ''arias'' in common usage; diminutive form: arietta, ; : ariette; in English simply air (music), air) is a self-contained piece for one voice, with or without instrument (music), instrumental or orchestral accompan ...

'' and its intergeneric hybrids (see below), the whitebeams, with simple leaves usually strongly white-hairy below (hence the name, from German ''Weissbaum'', 'white tree'); fruit carpels not fused; the type is '' Aria edulis'' (common whitebeam). Distribution: Europe,

Maghreb The Maghreb (; ), also known as the Arab Maghreb () and Northwest Africa, is the western part of the Arab world. The region comprises western and central North Africa, including Algeria, Libya, Mauritania, Morocco, and Tunisia. The Maghreb al ...

and western Asia. ;''Sorbus'' (''Micromeles'') * now genus '' Micromeles'', a group of east Asian species with narrow leaves; sometimes previously included in subgenus ''Aria''. Distribution: temperate and tropical east Asia. ;''Sorbus'' (''Cormus'') * now genus ''Cormus'', with compound leaves similar to subgenus ''Sorbus'', but with distinct fused carpels in the fruit; just one species, '' Cormus domestica'' (true service tree). Distribution: North Africa, warm-temperate Europe, western Asia. Used to flavour some apple wines, see '' Apfelwein''. ;''Sorbus'' (''Torminaria'') * now genus '' Torminalis'', with rather maple-like lobed leaves with ''pointed'' lobes; fruit carpels not fused; just one species (wild service tree). Distribution: warm-temperate Europe, south to the mountains of North Africa and east to the

Caucasus The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, i ...

and

Lebanon Lebanon, officially the Republic of Lebanon, is a country in the Levant region of West Asia. Situated at the crossroads of the Mediterranean Basin and the Arabian Peninsula, it is bordered by Syria to the north and east, Israel to the south ...

ranges. ;''Sorbus'' (''Chamaemespilus'') * now genus '' Chamaemespilus'', monotypic, with a single shrubby species, false medlar. Has simple, glabrous leaves and pink flowers with erect sepals and petals. Distribution: mountains of southern Europe. Intergeneric hybrid genera * '' Hedlundia - Aria × Sorbus'' hybrids * '' Karpatiosorbus'' - ''Aria'' × ''Torminalis'' hybrids * '' Majovskya'' - ''Aria'' × ''Chamaemespilus'' hybrids * '' Scandosorbus'' - syn. ''Borkhausenia''; ''Aria'' × ''Sorbus'' × ''Torminalis'' hybrids * '' Normeyera'' - ''Aria'' × ''Chamaemespilus'' × ''Sorbus'' hybrids

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. The following, of mixed or uncertain parentage, have gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

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

: * 'Eastern Promise' (purple autumn colour, pink berries) * 'Leonard Messel' named for Leonard Messel of Nymans in Sussex. (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 Lijsterbes (Sorbus). 31-03-2024 (d.j.b.) 02.jpg, New leaf from one ''Sorbus'' opens up.

Genus

Uses

Ornamental trees

Gallery

References

Further reading