There are two basic categories of orange: the sweet orange (C. sinensis) and the bitter orange (C. aurantium).
Sweet orange varieties
Sweet orange is divided into four classes, each with distinct characteristics:
Common orange – There are many varieties of common orange and it is widely grown. The most common varieties of common oranges are the Valencia, Hart’s Tardiff Valencia, and the Hamlin, but there are dozens of other types.
Blood or pigmented orange – The blood orange consists of two types: the light blood orange and the deep blood orange. Blood oranges are a natural mutation of C. sinensis. High amounts of anthocyanin give the entire fruit its deep red hue. In the blood orange category, varieties of orange fruit include: Maltese, Moro, Sanguinelli, Scarlet Navel and Tarocco.
Navel orange – The navel orange is of great commercial import and we know it well as the most common orange sold at the grocers. Of the navels, the most common types are the Cara cara, Bahia, Dream navel, Late Navel and Washington or California Navel.
Acid-less orange – Acid-less oranges have very little acid, hence little flavor. Acid-less oranges are early season fruit and are also called “sweet” oranges. They contain very little acid, which protects against spoilage, thus rendering them unfit for juicing. They are not generally cultivated in large quantities.
Also included among the sweet common orange varieties is an original citrus species, the mandarin. Amongst its many cultivars are:
Satsuma
Tangerine
Clementine