Just back [details coming later in the week] and I find that Sicily can still surprise me, for I had never seen these on sale before:
Come to think of it, I had never seen them anywhere and I wasn't the only one, as even elderly Sicilians were asking the greengrocer what they were. Sorbe is the answer and I gather they are related to rowans and are the fruit of this tree. They seem to be a largely forgotten fruit and these come from the Etna area. The greengrocer said they can be eaten when they turn brown and I can tell you that they have a pleasant, peary taste.
Più si vive, più s'impara - you live and learn.