''Sorbus rupicola'', known as rock whitebeam,
is a rare shrub or small tree best known from the
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...
but also reported from
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
,
Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
and
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
.
Reaching heights of 10 m,
[''New Flora of the British Isles''; ]Clive Stace
Clive Anthony Stace (born 1938) is a British botanist and botanical author. He studied at King's College London, graduated from University of London in 1959 and then studied at the Natural History Museum, London. He was awarded a PhD in 1963. H ...
; Third edition; 2011 printing it grows in rocky woodland, scrub and cliffs, usually on limestone.
The species reproduces
apomictically (asexually via cloned seeds) and was presumably created by
autopolyploidysation of the common whitebeam proper (''
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 ...
s.str.''). It contains a tetraploidal set of
chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s (2n=4x=68).
''Sorbus rupicola'' is a member of ''Sorbus aria''
agg., which contains 20 subspecies. A key to this aggregate is given in Stace - though be warned Stace states "It is probably impossible to construct a reliable key to the agg."!
Stace gives ''Sorbus rupicola'' the following characteristics:
* Leaves unlobed or lobed ≤1/20 of the way to the midrib.
* Leaves with a single style of teeth or, weakly, two styles of teeth.
* Leaves with 6 to 9 (rarely 4 to 10) pairs of lateral veins.
* Leaves mostly 1.6 to 2.4 times longer than wide.
* Leaves mostly widest in that half of the leaf furthest from the stalk.
* Leaves usually obtuse (rarely acute) at apex.
* Leaves have dense white hairs on lower surface.
* Fruits 10-15mm across, warty.
Rock Whitebeam-young plant.jpg, A young specimen
Rock Whitebeam-leaf lower.jpg, Back of a leaf
Rock Whitebeam-leaf upper 1.jpg, Upper surface of a leaf
Rock Whitebeam-leaf upper 2.jpg, Upper surface of a leaf
Rock Whitebeam-twig.jpg, Twig and part of a leaf
References
Further reading
*
*
External links
Distribution map of ''S. rupicola'' Naturhistoriska riksmuseet
The Swedish Museum of Natural History ( sv, Naturhistoriska riksmuseet, literally, the National Museum of Natural History), in Stockholm, is one of two major museums of natural history in Sweden, the other one being located in Gothenburg.
The ...
.
{{Taxonbar, from=Q1335724
rupicola
Flora of Europe