Rowan or Sorbus aucuparia.
Sorbus aucuparia
The Mountain Ash is Sorbus aucuparia. I know of no tree called the Rocky Mountain Ash.
Fraxinus ornus
Fraxinus americana.
Rowan the Mountain Ash
The name would be Fraxinus excelsior.
Sorbus americana
The name would be Fraxinus americana.
Fraxinus excelsior (European) Family: Oleaceae.
The scientific or taxonomic name would be Pristiphora geniculata.
The scientific name for an ash hawthorn tree is Crataegus tomentosa.
Yes Answer' The mountain ash is Sorbus aucuparia.
Scientific names (usually based on Latin or Greek words) are given to organisms to specifically identify them. This classification is based, where possible, on how the organisms are related genetically. There are several trees in Australia , for example, that are commonly called "Mountain Ash". One of them, with the scientific name, Eucalyptus regnans, grows in Victoria and is the tallest tree in Australia. A group of Americans once asked to be sent seeds of the Australian Mountain Ash. They were probably disappointed when they were accidently sent seeds of the Tasmanian "Mountain Ash", a somewhat smaller species of Eucalytus.