This is the last day of my short vacation, so only a brief entry with links today. Do visit the original image to read edgeplot’s notes about this particular cultivar. I’ve chosen to drop the epithet boliviensis from the name, following the RHS Plant Finder’s convention. Still, it is evident that Begonia boliviensis is responsible for much of the appearance of this attractive cultivar.
Wikipedia’s entry on begonia is a worthwhile read. I hadn’t realized that Begonia is among the ten largest genera of plants.