| Hedlundia arranensis | |
|---|---|
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Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Rosales |
| Family: | Rosaceae |
| Genus: | Hedlundia |
| Species: | H. arranensis |
| Binomial name | |
| Hedlundia arranensis (Hedl.) Sennikov & Kurtto | |
| Synonyms | |
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Hedlundia arranensis, sometimes referred to as the Scottish or Arran whitebeam, is a species of plant in the family Rosaceae. It is endemic to the island of Arran in Scotland.
The species is threatened by habitat loss and only 283 Hedlundia arranensis were recorded as mature trees in 1980. [2] 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 (SSSI), and is monitored by staff from NatureScot. [3] 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 specimens exist.
The whitebeams are 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 ) giving rise to the more robust rock whitebeam ( Aria rupicola ) which is still found on Holy Isle. This hybrid species interbred with the rowan/mountain ash ( Sorbus aucuparia ) to produce H. arranesis. The bastard mountain ash ( Hedlundia pseudofennica ) 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. [4]
The Islands of the Firth of Clyde are the fifth largest of the major Scottish island groups after the Inner and Outer Hebrides, Orkney and Shetland. They are situated in the Firth of Clyde between Ayrshire and Argyll and Bute. There are about forty islands and skerries. Only four are inhabited, and only nine are larger than 40 hectares. The largest and most populous are Arran and Bute. They are served by dedicated ferry routes, as are Great Cumbrae and Holy Island. Unlike the isles in the four larger Scottish archipelagos, none of the isles in this group are connected to one another or to the mainland by bridges.
The Holy Island or Holy Isle is an island in the Firth of Clyde, off the west coast of central Scotland, inside Lamlash Bay on the larger Isle of Arran. The island is around 3 kilometres long and around 1 kilometre wide. Its highest point is the hill Mullach Mòr.
The rowans or mountain-ashes are shrubs or trees in the genus Sorbus of the rose family, Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the Himalaya, southern Tibet and parts of western China, where numerous apomictic microspecies occur. The name rowan was originally applied to the species Sorbus aucuparia and is also used for other species in the genus 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 depending on the circumscription of the genus, and also due to the number of apomictic microspecies, which some treat as distinct species, but others group in a smaller number of variable species. Recent treatments classify Sorbus in a narrower sense to include only the pinnate leaved species of subgenus Sorbus, raising several of the other subgenera to generic rank.
Catacol is a small village on the Isle of Arran, Scotland.
The Arran whitebeams are species of whitebeam endemic to the island of Arran, Ayrshire, Scotland.
Hedlundia pseudomeinichii, known as false rowan and Catacol whitebeam, is a rare species of tree endemic to the Isle of Arran in south-western Scotland. It is believed to have arisen as a hybrid of the native European rowan and the cut-leaved whitebeam which is in turn a rowan/Arran whitebeam hybrid. Until 2020, only one living specimens of the Catacol whitebeam was known, at the time making it the rarest tree not only in Scotland, but joint rarest in the world with Wood's cycad. Another was recorded as a sapling, but is believed to have been destroyed by deer. A seedling and grafted plants have also been grown in Edinburgh.
Hedlundia anglica, the English whitebeam, is a species of whitebeam tree in the family Rosaceae. It is uncommonly found in Ireland and the United Kingdom, with an entire British population estimated at about 600 individuals.
Sorbus leyana. Ley's whitebeam is a species of small tree which is endemic to two sites in southern Wales. It is thought to have arisen by hybridisation of two species of Sorbus, one of which was the rowan. Its closest relatives are some of the other hybrid derived Sorbus species found in Britain.
Sorbus maderensis is a species of rowan in the family Rosaceae that is endemic to Madeira. It is threatened by habitat loss.
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 occurring hybrid between H. arranensis and Sorbus aucuparia, probably with additional backcrossing with S. aucuparia. Hedlundia arranensis is itself a hybrid between Aria rupicola and S. aucuparia. Apomixis and hybridization are common in some groups of Sorbus species.
Hedlundia hybrida, the oakleaf mountain ash, Swedish service-tree or Finnish whitebeam, is a species of whitebeam native to Norway, eastern Sweden, south-western Finland, and locally in Latvia.
Sorbus minima, commonly known as the lesser whitebeam or least whitebeam, is a shrub belonging to the subgenus Aria (whitebeams) in the genus Sorbus. It is endemic to Wales where it grows at a few sites in Breconshire. It is an apomictic microspecies which reproduces asexually and so is reproductively isolated from its close relatives such as the Swedish whitebeam, S. intermedia. It probably originated as a hybrid between the rock whitebeam and the rowan. It was first discovered in 1893 by Augustin Ley, the vicar of Sellack in Herefordshire who travelled widely in Wales.
The flora of Scotland is an assemblage of native plant species including over 1,600 vascular plants, more than 1,500 lichens and nearly 1,000 bryophytes. The total number of vascular species is low by world standards but lichens and bryophytes are abundant and the latter form a population of global importance. Various populations of rare fern exist, although the impact of 19th-century collectors threatened the existence of several species. The flora is generally typical of the north-west European part of the Palearctic realm and prominent features of the Scottish flora include boreal Caledonian forest, heather moorland and coastal machair. In addition to the native species of vascular plants there are numerous non-native introductions, now believed to make up some 43% of the species in the country.
The Isle of Arran or simply Arran is an island off the west coast of Scotland. It is the largest island in the Firth of Clyde and the seventh-largest Scottish island, at 432 square kilometres (167 sq mi). Historically part of Buteshire, it is in the unitary council area of North Ayrshire. In the 2011 census it had a resident population of 4,629. Though culturally and physically similar to the Hebrides, it is separated from them by the Kintyre peninsula. Often referred to as "Scotland in Miniature", the Island is divided into highland and lowland areas by the Highland Boundary Fault and has been described as a "geologist's paradise".
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.
Scotland is ideal for tree growth, thanks to its mild winters, plentiful rainfall, fertile soil and hill-sheltered topography. As of 2019 about 18.5% of the country was wooded. Although this figure is well below the European Union (EU) average of 43%, it represents a significant increase compared to the figure of 100 years previously: in 1919 it was estimated that only 5% of the country's total land area was covered in forest. The Scottish Government's Draft Climate Change Plan has set an aim of increasing coverage to 21% of Scotland by 2032, with the rate of afforestation rising to 15,000 hectares per year by 2024.
Aria hibernica, commonly known as Irish whitebeam, is a species of whitebeam endemic to Ireland. It occurs in most counties, usually as scattered individuals, or in small groups.
Hedlundia is a genus of plants in the rose family. They are shrubs or small trees that have a hybrid origin involving crosses between Aria and Sorbus sensu stricto. There are about 48 species are distributed across central, western and southern Europe, Scandinavia, Turkey, the Caucasus, Crimea, and also central Asia. The term Hedlundia was published in 2017.
