The many varieties of Seville sour oranges

In addition to the classic Seville sour oranges, there exist many variant or hybrid types and mutations, a few of which are available commercially in small quantities in California. Here’s a guide to some of the most important or interesting of these.

* Bittersweet. Compared with standard sour oranges, varieties of this type, such as Paraguay, have lower acidity and bitterness, so they can almost be eaten fresh with pleasure. An odd sidelight: After the War of the Triple Alliance (1865-70) reduced the population of Paraguay by 60%, feral sour orange trees covered abandoned farms. A French botanist, Benjamin Balansa (1825-92), organized the gathering and distillation of sour orange leaves and twigs to yield oil of petitgrain, used in soaps, cosmetics and flavorings, and Paraguay became the world’s largest producer. Today petitgrain comes almost entirely from cultivated plantings.

* Bouquetier. Class of variant sour oranges with abundant flowers used for making oil of neroli, an important ingredient in perfume. Varieties include Bouquet de Fleurs and Bouquetier à Grandes Fleurs. Trees and fruits are available on a small scale in California.

* Chinotto. Ornamental varieties with dense foliage of myrtle-like leaves, bearing numerous small, round, deep orange fruits, which are candied whole in France and Italy; also used to flavor San Pellegrino water. Available on a small scale in California.

* Citrus miaray. Sour orange hybrid, small (golf ball-size) with a slight neck; thin orange rind, easy to peel; juicy, light orange flesh, extremely acrid and unpleasant, with notes of sulfur. An oddity at the UC Riverside Citrus Variety Collection, so foul that it should be against the Geneva Conventions to feed it to prisoners.

* Horned. A bizarre ornamental mutation with horn-like protuberances, known in Italy since the 17th century. The Oscar Tintori Nursery of Pescia, Italy, donated budwood of this rarity last April to the USDA quarantine facility in Riverside.

* Seville. Medium to large, round, deep reddish orange; flesh yellow, seedy; juice bitter and sour. The common sour orange used as a rootstock and grown in southern Spain and California for making marmalade. It’s really a group of similar clones, selected for vigor, freedom from thorns and good productivity. In Spain it’s called Sevillano, Agria de Espana, and Real. In California there exist at least half a dozen selections, such as Standard, Keen, Rubidoux, Olivelands, Tunisian and even one named Seville; they differ somewhat in characteristics such as size, thickness of rind and juiciness of flesh, but are all marketed commercially as “Seville.” Season January and February in the San Joaquin Valley, a month later in coastal Southern California.

* Variegated. Mutation of standard sour orange with thin, smooth, lemon-yellow stripes on the rind, from the Murphy Oil Co. nursery, Whittier, 1914. Some leaves too are variegated.

-- David Karp