The bitter orange, a medicinal fruit indigenous to China and India, was introduced by the Romans to the Mediterranean from Arabia, and by the Arabs to Spain. The tree in fruit, laden, is an apparition as in a mediaeval painting.
The fruits are smaller than oranges and are, of course, the ones used in orange marmalade. Marmalade made with the freshly picked fruit has a more ‘sparkling’ taste than that of English marmalades: use 8 bitter oranges and 2 lemons to 1 kg (2¼ lb) sugar, and a freshly picked bayleaf.