Complex sentence: Formerly, when a wider variety of fruits were commonly eaten in Europe and North America, "Sorbus" was a domestically used fruit, but "Sorbus domestica" is now all but extinct in Britain, where it was traditionally revered.
Split into simpler sentences: Formerly, when a wider variety of fruits were commonly eaten in Europe and North America, "Sorbus" was a domestically used fruit throughout these regions. It is still used in some countries, but "Sorbus domestica", for example, is now all but extinct in Britain, where it was traditionally revered.