Two closely related berries. The mirtillo nero is the European blueberry, also known as whortleberry or bilberry. The less common mirtillo rosso is the lingonberry, but also suffices for cranberry, especially around Christmas (salsa di mirtillo is cranberry sauce). In Trentino they are called garnetole.
No one will ever go broke selling American-style blueberry muffins in Italy, but the Italians also like to put both kinds of mirtilli in more traditional desserts and jam, in risottos and sometimes even on pasta.
Images by: Unsplash, Jyrki Kymäläinen