Any citrus fruit can be used for making marmalade. Bitter or sweet oranges, lemons, grapefruit, tangerines, satsumas and ugli fruit, on their own or in various combinations.
Flavorings such as ginger, whisky, rum, brandy, treacle and apricots can be added but the citrus flavor must predominate. See how to make some below.
(Picture Credit: onehundreddollarsamonth.com)