''Sorbus minima'', commonly known as the lesser whitebeam or least whitebeam, is a

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

belonging to the

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 ...

''Aria'' (

whitebeam The whitebeams are members of the family Rosaceae, comprising subgenus ''Aria'' (or, according to some authorities, its own genus) of genus ''Sorbus'', and hybrids involving species of this subgenus and members of subgenera ''Sorbus'', ''Torminar ...

s) in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 depend ...

''. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

where it grows at a few sites in

Breconshire , image_flag= , HQ= Brecon , Government= Brecknockshire County Council (1889-1974) , Origin= Brycheiniog , Status= , Start= 1535 , End= ...

. It is an apomictic microspecies which reproduces asexually and so is

reproductively isolated The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring ...

from its close relatives such as the Swedish whitebeam, '' S. intermedia''. It probably originated as a

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

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 Herefordshire () is a county in the West Midlands of England, governed by Herefordshire Council. It is bordered by Shropshire to the north, Worcestershire to the east, Gloucestershire to the south-east, and the Welsh counties of Monmouthshire ...

who travelled widely in Wales. It is a slender,

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

shrub which can reach three metres in height. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are 6–8 centimetres long and are fairly narrow and oval in shape being 1.8–2.2 times as long as they are broad. They are acutely pointed at the tip and base, have 7–10 (usually 8 or 9) pairs of

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

and are lobed one fifth to one third of the way to the

midrib This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are produced in May and June and their

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s are 4 millimetres long and white. The red

berries A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...

are 6–8 millimetres across with a few small

lenticel A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a ...

s. It grows on

carboniferous limestone Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian Epoch of the Carboniferous Period. These rocks formed between 363 and ...

cliffs near

Crickhowell Crickhowell (; cy, Crucywel , non-standard spelling ') is a town and community in southeastern Powys, Wales, near Abergavenny, and is in the historic county of Brecknockshire. Location The town lies on the River Usk, on the southern edge ...

in the eastern

Brecon Beacons The Brecon Beacons ( cy, Bannau Brycheiniog, ) are a mountain range in South Wales. In a narrow sense, the name refers to the range of Old Red Sandstone peaks which lie to the south of Brecon. Sometimes referred to as "the central Beacons" t ...

. The largest population is at

Craig y Cilau Craig y Cilau is a limestone escarpment in the Brecon Beacons National Park in Powys, Wales. It was declared a national nature reserve in 1959 because of its importance for wildlife, particularly plants. It is situated on the north side of Myny ...

National Nature Reserve where, in September 2002, 730 plants were counted within the reserve with several more in surrounding areas. Smaller numbers grow further west at Cwm Cleisfer and a single plant remains at Craig y Castell. It formerly also occurred at Blaen Onneu. In 1947 the species was endangered by British Army mortar practice in and around its habitat. By raising the issue in the Commons, and inducing

War Secretary The Secretary of State for War, commonly called War Secretary, was a secretary of state in the Government of the United Kingdom, which existed from 1794 to 1801 and from 1854 to 1964. The Secretary of State for War headed the War Office and ...

Frederick Bellenger Captain Frederick John Bellenger (23 July 1894 – 11 May 1968) was a British surveyor, soldier and politician. Early life Born in Bethnal Green, London, he was the son of Eugene Bernard Bellenger, a dairyman, and his wife Isabella Annette ''n� ...

to order the Army to pull out of the area, Tudor Watkins,

Labour Labour or labor may refer to: * Childbirth, the delivery of a baby * Labour (human activity), or work ** Manual labour, physical work ** Wage labour, a socioeconomic relationship between a worker and an employer ** Organized labour and the labour ...

MP for Brecon and Radnorshire is crediting with preserving the species from extinction.Jones, David. ''Welsh Wildlife'' (''It's Wales'' series). Talybont: Y Lolfa, 2003; p. 41 The species has been affected by

quarrying A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their environ ...

which has destroyed many plants and reduced the amount of available

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

. It can recolonize disused quarries but does not reach the same population density as at undisturbed sites. All the locations where the species grows, apart from Cwm Cleisfer, now have some kind of protection and a population is kept at the

National Botanic Garden of Wales The National Botanic Garden of Wales ( cy, Gardd Fotaneg Genedlaethol Cymru) is a botanical garden located in Llanarthney in the River Tywi valley, Carmarthenshire, Wales. The garden is both a visitor attraction and a centre for botanical rese ...

Sources

*Ellis, R. G. (1983) ''Flowering Plants of Wales''. National Museum of Wales, Cardiff. * * Stace, Clive A. (1997) ''New Flora of the British Isles''. Cambridge University Press. *Tutin, T. G. ''et al.'' (1968) ''

Flora Europaea The ''Flora Europaea'' is a 5-volume encyclopedia of plants, published between 1964 and 1993 by Cambridge University Press. The aim was to describe all the national Floras of Europe in a single, authoritative publication to help readers identify ...

'', Volume 2. Cambridge University Press.

References

External links

*
Photograph of the flower
{{Taxonbar, from=Q4118452

minima In mathematical analysis, the maxima and minima (the respective plurals of maximum and minimum) of a function, known collectively as extrema (the plural of extremum), are the largest and smallest value of the function, either within a given ran ...

Endemic flora of Wales Plants described in 1901