''Hedlundia arranensis'', sometimes referred to as the Scottish or Arran whitebeam, is a species of
plant
Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...
in the family
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 ...
. It is
endemic
Endemism is the state of a species being found only 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 foun ...
to the island of
Arran in Scotland.
Range and habitat
The species is threatened by
habitat loss
Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
and only 283 ''Hedlundia arranensis'' were recorded as mature trees in 1980.
They are protected in
Glen Diomhan off
Glen Catacol, which was formerly part of a
National Nature Reserve; although this designation was removed in 2011 the area continues to form part of a designated
Site of Special Scientific Interest
A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...
(SSSI), and is monitored by staff from
NatureScot
NatureScot () is an Scottish public bodies#Executive NDPBs, executive non-departmental public body of the Scottish Government responsible for Scotland’s natural heritage, especially its nature, natural, genetics, genetic and scenic diversity. ...
.
In its native states its distribution is restricted to Abhainn Bheag (Uisge Solus), Glen Diomhan (and tributary), Glen Catacol, Allt nan Calman, ''Allt Dubh'', Gleann Easan Biorach and Glen Iorsa (''Allt-nan-Champ''). The trees are found in small remnants of woodland on inaccessible steep slopes, and grow on acidic soils.
''Hedlundia arranensis'' evoked most collecting interest in 1870–1890 and 1920–1940, although older
herbarium
A herbarium (plural: herbaria) is a collection of preserved plant biological specimen, specimens and associated data used for scientific study.
The specimens may be whole plants or plant parts; these will usually be in dried form mounted on a sh ...
specimens exist.
Evolution
The whitebeams are
apomictic
In botany, apomixis is asexual reproduction, asexual development of seed or embryo without Fertilisation, fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils.
Apomictic ...
, producing viable seed without the need for pollination and fertilisation. Each time this occurs, a new
clone is effectively produced. The trees developed in a highly complex fashion, which involved the common whitebeam (''
Aria edulis
''Aria edulis'', the whitebeam or common whitebeam, is a species of deciduous tree in the family ''Rosaceae''.
The tree often forms new shoots around the trunk. Typically compact and domed, the plant has a few upswept branches and the leaves ha ...
'') giving rise to the more robust rock whitebeam (''
Aria rupicola
''Aria rupicola'', commonly known as rock whitebeam, is a rare species of shrub or small tree best known from the British Isles but also reported from Norway, Sweden and Russia.
Reaching heights of 10 m,''New Flora of the British Isles''; Clive ...
'') which is still found on
Holy Isle. This hybrid species interbred with the rowan/mountain ash (''
Sorbus aucuparia
''Sorbus aucuparia'', commonly called rowan (, also ) and mountain-ash, is a species of deciduous tree or shrub in the rose family.
The tree has a slender trunk with smooth bark, a loose and roundish crown, and its leaves are pinnate in pairs o ...
'') to produce ''H. arranesis''. The bastard mountain ash (''
Hedlundia pseudofennica
''Hedlundia pseudofennica'', also called Arran service-tree or Arran cut-leaved whitebeam, is a species of plant in the family Rosaceae. Endemic to the Isle of Arran in Scotland, it is threatened by habitat loss. It is thought to be a naturally ...
'') arose from a further cross between ''H. arranensis'' and the mountain ash (''S. aucuparia'').
Smart showed by using physical characteristics that the species were separate and not a result of random variation. Some overlap does however occur and this suggests that some hybridising may occur between ''H. arranensis'' and ''H. pseudofennica''.
See also
*
Arran Whitebeams
References
{{Taxonbar, from1=Q41133064, from2=Q1948627
Flora of the United Kingdom
arranensis
Vulnerable plants
Endemic flora of Scotland
Endemic biota of the Scottish islands
Isle of Arran
Taxonomy articles created by Polbot