Species of shrub
Aria rupicola, commonly known as rock whitebeam,[1] is a rare species of shrub or small tree best known from the British Isles but also reported from Norway, Sweden and Russia.[2]
Reaching heights of 10 m,[3] it grows in rocky woodland, scrub and cliffs, usually on limestone.[3]
The species reproduces apomictically (asexually via cloned seeds) and was presumably created by autopolyploidysation of the common whitebeam proper (Sorbus aria s.str.). It contains a tetraploidal set of chromosomes (2n=4x=68).
Stace gives Aria rupicola the following characteristics:[3]
- 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.
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A young specimen
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Back of a leaf
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Upper surface of a leaf
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Upper surface of a leaf
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Twig and part of a leaf
References
Further reading
External links
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| Aria rupicola | |
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| Sorbus rupicola | |
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