Arran whitebeams complex fashion, which involved the common whitebeam ("Sorbus aria") giving rise to the tetraploid rock whitebeam ("Sorbus rupicola") which is still found on Holy Isle. This species is able to survive at higher altitudes and therefore occupies a less competitive niche with fewer tree species able to tolerate the harsher conditions. The rock whitebeam interbred with the rowan / mountain ash ("Sorbus aucuparia") to produce the hybrid, a fertile separate species the Scottish whitebeam ("Sorbus arranesis") which grows well in this zone of reduced competitive growth at higher altitudes. The bastard mountain ash ("Sorbus pseudofennica") arose from a further cross
Mountain Ash railway station The frequency drops to hourly in the evening, On Sundays there is a general 2-hourly service to Barry Island with an hourly service in the morning and in the late afternoon. This is due to a campaign by the local Assembly Member and a sucsesful trial in December 2017. The extra services began in April 2018. Mountain Ash railway station Mountain Ash railway station (Welsh: Gorsaf Reilffordd Aberpennar) is a railway station serving the town of Mountain Ash in Rhondda Cynon Taf, Wales. It is located on the Aberdare branch of the Merthyr Line. It is also located on the