''Salix euxina'', the eastern crack-willow, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the willow family

Salicaceae The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae ''sensu stricto'') included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly ...

, native from Turkey to the Caucasus. It was first described by I. V. Belyaeva in 2009. It is one of the parents of the common crack-willow, ''Salix'' × ''fragilis''.

Description

''Salix euxina'' is a tree which can reach 15–20 m high with a trunk diameter of up to 1 m. It has a wide crown, and old trees develop deeply fissured bark on their trunks. The olive green branchlets are hairless (glabrous) and very brittle at the base, so that branches easily break off. These are able to root and propagate the species. The leaves are pale green and glabrous. They have stomata only on the undersurface. The catkins are relatively thick with somewhat densely clustered flowers. ''Salix'' × ''fragilis'', the hybrid between ''Salix euxina'' and ''

Salix alba ''Salix alba'', the white willow, is a species of willow native to Europe and western and central Asia.Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. .Rushforth, K. (1999). ''Trees of Britain an ...

'', has hairs on its branches and branchlets, stomata on both surfaces of its leaves, and slender, more loosely flowered catkins.

Taxonomy

In 1753,

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...

described the species ''Salix fragilis''. From at least the 1920s, botanists applied Linnaeus's name "''Salix fragilis''" both to a pure species and to its hybrid with ''

''. In 2009, the Nomenclature Committee for Vascular Plants decided to conserve the name "''Salix fragilis''" for the hybrid, and Irina V. Belyaeva then described the previously unnamed parent species as ''Salix euxina''. The epithet ''euxina'' refers to the distribution of the species around the

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...

, known as () in

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

Distribution and habitat

''Salix euxina'' is native to a narrow region around the east of the

, including northern

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...

, the

North Caucasus The North Caucasus, ( ady, Темыр Къафкъас, Temır Qafqas; kbd, Ишхъэрэ Къаукъаз, İṩxhərə Qauqaz; ce, Къилбаседа Кавказ, Q̇ilbaseda Kavkaz; , os, Цӕгат Кавказ, Cægat Kavkaz, inh, ...

and the

Transcaucasus The South Caucasus, also known as Transcaucasia or the Transcaucasus, is a geographical region on the border of Eastern Europe and Western Asia, straddling the southern Caucasus Mountains. The South Caucasus roughly corresponds to modern Arme ...

, where it is found beside mountain streams. It has been introduced into parts of Europe (Belgium, European Russia, Great Britain and the Netherlands) and Canada (

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

and

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

). In Europe, it is much less common than the hybrid ''S. fragilis'', making up only around 10% of all specimens.

Cultivation

The name "''Salix fragilis''" was applied in cultivation to plants now recognized as either ''S.'' × ''fragilis'', ''S. alba'' or ''S. euxina''. One cultivar identified as ''S. euxina'' is 'Bullata', popular as an ornamental tree in Europe. It has a short trunk and a very dense globe-shaped crown.

References

{{taxonbar, from1=Q18119933 euxina Flora of Turkey Flora of the Caucasus Plants described in 2009